diff --git a/modules/openapi-generator/src/main/resources/php/model_generic.mustache b/modules/openapi-generator/src/main/resources/php/model_generic.mustache
index 067202027d11..e71aaa8360df 100644
--- a/modules/openapi-generator/src/main/resources/php/model_generic.mustache
+++ b/modules/openapi-generator/src/main/resources/php/model_generic.mustache
@@ -378,7 +378,7 @@ class {{classname}} {{#parentSchema}}extends {{{parent}}}{{/parentSchema}}{{^par
     /**
      * Sets {{name}}
      *
-     * @param {{{dataType}}}{{#isNullable}}|null{{/isNullable}} ${{name}}{{#description}} {{{.}}}{{/description}}{{^description}} {{{name}}}{{/description}}
+     * @param {{{dataType}}}{{^required}}|null{{/required}}{{#required}}{{#isNullable}}|null{{/isNullable}}{{/required}} ${{name}}{{#description}} {{{.}}}{{/description}}{{^description}} {{{name}}}{{/description}}
      *
      * @return self
     {{#deprecated}}
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php
index ecc9f2b000ad..7b1d78543379 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php
@@ -309,7 +309,7 @@ public function getMapProperty()
     /**
      * Sets map_property
      *
-     * @param array<string,string> $map_property map_property
+     * @param array<string,string>|null $map_property map_property
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getMapOfMapProperty()
     /**
      * Sets map_of_map_property
      *
-     * @param array<string,array<string,string>> $map_of_map_property map_of_map_property
+     * @param array<string,array<string,string>>|null $map_of_map_property map_of_map_property
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AllOfWithSingleRef.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AllOfWithSingleRef.php
index 3c3a1a9bfc88..a198a937a5ba 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AllOfWithSingleRef.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AllOfWithSingleRef.php
@@ -309,7 +309,7 @@ public function getUsername()
     /**
      * Sets username
      *
-     * @param string $username username
+     * @param string|null $username username
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getSingleRefType()
     /**
      * Sets single_ref_type
      *
-     * @param \OpenAPI\Client\Model\SingleRefType $single_ref_type single_ref_type
+     * @param \OpenAPI\Client\Model\SingleRefType|null $single_ref_type single_ref_type
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php
index a03b0faa840c..ff733fda6512 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php
@@ -342,7 +342,7 @@ public function getColor()
     /**
      * Sets color
      *
-     * @param string $color color
+     * @param string|null $color color
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php
index a8a4a7682bf7..f0999711bbbe 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php
@@ -316,7 +316,7 @@ public function getCode()
     /**
      * Sets code
      *
-     * @param int $code code
+     * @param int|null $code code
      *
      * @return self
      */
@@ -343,7 +343,7 @@ public function getType()
     /**
      * Sets type
      *
-     * @param string $type type
+     * @param string|null $type type
      *
      * @return self
      */
@@ -370,7 +370,7 @@ public function getMessage()
     /**
      * Sets message
      *
-     * @param string $message message
+     * @param string|null $message message
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php
index bef6d5bdfc0e..2be31050ba4a 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php
@@ -302,7 +302,7 @@ public function getArrayArrayNumber()
     /**
      * Sets array_array_number
      *
-     * @param float[][] $array_array_number array_array_number
+     * @param float[][]|null $array_array_number array_array_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php
index 9a9e9c4cb70e..83db4149ab65 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php
@@ -302,7 +302,7 @@ public function getArrayNumber()
     /**
      * Sets array_number
      *
-     * @param float[] $array_number array_number
+     * @param float[]|null $array_number array_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php
index ba7df9ff7379..7b68751714a4 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php
@@ -324,7 +324,7 @@ public function getArrayOfString()
     /**
      * Sets array_of_string
      *
-     * @param string[] $array_of_string array_of_string
+     * @param string[]|null $array_of_string array_of_string
      *
      * @return self
      */
@@ -358,7 +358,7 @@ public function getArrayArrayOfInteger()
     /**
      * Sets array_array_of_integer
      *
-     * @param int[][] $array_array_of_integer array_array_of_integer
+     * @param int[][]|null $array_array_of_integer array_array_of_integer
      *
      * @return self
      */
@@ -385,7 +385,7 @@ public function getArrayArrayOfModel()
     /**
      * Sets array_array_of_model
      *
-     * @param \OpenAPI\Client\Model\ReadOnlyFirst[][] $array_array_of_model array_array_of_model
+     * @param \OpenAPI\Client\Model\ReadOnlyFirst[][]|null $array_array_of_model array_array_of_model
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php
index 5bd9fe1b6670..3204141d9263 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php
@@ -337,7 +337,7 @@ public function getSmallCamel()
     /**
      * Sets small_camel
      *
-     * @param string $small_camel small_camel
+     * @param string|null $small_camel small_camel
      *
      * @return self
      */
@@ -364,7 +364,7 @@ public function getCapitalCamel()
     /**
      * Sets capital_camel
      *
-     * @param string $capital_camel capital_camel
+     * @param string|null $capital_camel capital_camel
      *
      * @return self
      */
@@ -391,7 +391,7 @@ public function getSmallSnake()
     /**
      * Sets small_snake
      *
-     * @param string $small_snake small_snake
+     * @param string|null $small_snake small_snake
      *
      * @return self
      */
@@ -418,7 +418,7 @@ public function getCapitalSnake()
     /**
      * Sets capital_snake
      *
-     * @param string $capital_snake capital_snake
+     * @param string|null $capital_snake capital_snake
      *
      * @return self
      */
@@ -445,7 +445,7 @@ public function getScaEthFlowPoints()
     /**
      * Sets sca_eth_flow_points
      *
-     * @param string $sca_eth_flow_points sca_eth_flow_points
+     * @param string|null $sca_eth_flow_points sca_eth_flow_points
      *
      * @return self
      */
@@ -472,7 +472,7 @@ public function getAttName()
     /**
      * Sets att_name
      *
-     * @param string $att_name Name of the pet
+     * @param string|null $att_name Name of the pet
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php
index 13b65964a256..80c58c4b584e 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php
@@ -296,7 +296,7 @@ public function getDeclawed()
     /**
      * Sets declawed
      *
-     * @param bool $declawed declawed
+     * @param bool|null $declawed declawed
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php
index 4d953336f5b0..7397c09d5546 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php
@@ -312,7 +312,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php
index 9a9b24087484..373bbdc6225f 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php
@@ -303,7 +303,7 @@ public function getClass()
     /**
      * Sets _class
      *
-     * @param string $_class _class
+     * @param string|null $_class _class
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php
index a5dc5538b192..29699d28b0d8 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php
@@ -302,7 +302,7 @@ public function getClient()
     /**
      * Sets client
      *
-     * @param string $client client
+     * @param string|null $client client
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DeprecatedObject.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DeprecatedObject.php
index fb82b38d25c5..46c011375d64 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DeprecatedObject.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DeprecatedObject.php
@@ -302,7 +302,7 @@ public function getName()
     /**
      * Sets name
      *
-     * @param string $name name
+     * @param string|null $name name
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php
index b6f90c3bd183..58890d772e13 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php
@@ -296,7 +296,7 @@ public function getBreed()
     /**
      * Sets breed
      *
-     * @param string $breed breed
+     * @param string|null $breed breed
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php
index 7711c0ba6a10..b5c179f6a170 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php
@@ -348,7 +348,7 @@ public function getJustSymbol()
     /**
      * Sets just_symbol
      *
-     * @param string $just_symbol just_symbol
+     * @param string|null $just_symbol just_symbol
      *
      * @return self
      */
@@ -385,7 +385,7 @@ public function getArrayEnum()
     /**
      * Sets array_enum
      *
-     * @param string[] $array_enum array_enum
+     * @param string[]|null $array_enum array_enum
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php
index 1965d18994cf..6f863a21ac86 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php
@@ -454,7 +454,7 @@ public function getEnumString()
     /**
      * Sets enum_string
      *
-     * @param string $enum_string enum_string
+     * @param string|null $enum_string enum_string
      *
      * @return self
      */
@@ -528,7 +528,7 @@ public function getEnumInteger()
     /**
      * Sets enum_integer
      *
-     * @param int $enum_integer enum_integer
+     * @param int|null $enum_integer enum_integer
      *
      * @return self
      */
@@ -565,7 +565,7 @@ public function getEnumNumber()
     /**
      * Sets enum_number
      *
-     * @param float $enum_number enum_number
+     * @param float|null $enum_number enum_number
      *
      * @return self
      */
@@ -636,7 +636,7 @@ public function getOuterEnumInteger()
     /**
      * Sets outer_enum_integer
      *
-     * @param \OpenAPI\Client\Model\OuterEnumInteger $outer_enum_integer outer_enum_integer
+     * @param \OpenAPI\Client\Model\OuterEnumInteger|null $outer_enum_integer outer_enum_integer
      *
      * @return self
      */
@@ -663,7 +663,7 @@ public function getOuterEnumDefaultValue()
     /**
      * Sets outer_enum_default_value
      *
-     * @param \OpenAPI\Client\Model\OuterEnumDefaultValue $outer_enum_default_value outer_enum_default_value
+     * @param \OpenAPI\Client\Model\OuterEnumDefaultValue|null $outer_enum_default_value outer_enum_default_value
      *
      * @return self
      */
@@ -690,7 +690,7 @@ public function getOuterEnumIntegerDefaultValue()
     /**
      * Sets outer_enum_integer_default_value
      *
-     * @param \OpenAPI\Client\Model\OuterEnumIntegerDefaultValue $outer_enum_integer_default_value outer_enum_integer_default_value
+     * @param \OpenAPI\Client\Model\OuterEnumIntegerDefaultValue|null $outer_enum_integer_default_value outer_enum_integer_default_value
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ErrorResponse.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ErrorResponse.php
index 320272b436b0..e036cf0ae754 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ErrorResponse.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ErrorResponse.php
@@ -309,7 +309,7 @@ public function getResponseCode()
     /**
      * Sets response_code
      *
-     * @param int $response_code response_code
+     * @param int|null $response_code response_code
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getError()
     /**
      * Sets error
      *
-     * @param string $error error
+     * @param string|null $error error
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FakeBigDecimalMap200Response.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FakeBigDecimalMap200Response.php
index de2e8dda7cd9..4db0ab564ba7 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FakeBigDecimalMap200Response.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FakeBigDecimalMap200Response.php
@@ -309,7 +309,7 @@ public function getSomeId()
     /**
      * Sets some_id
      *
-     * @param float $some_id some_id
+     * @param float|null $some_id some_id
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getSomeMap()
     /**
      * Sets some_map
      *
-     * @param array<string,float> $some_map some_map
+     * @param array<string,float>|null $some_map some_map
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php
index f643a577f0fb..c44266813d92 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php
@@ -303,7 +303,7 @@ public function getSourceUri()
     /**
      * Sets source_uri
      *
-     * @param string $source_uri Test capitalization
+     * @param string|null $source_uri Test capitalization
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php
index 5c79651aaf64..b68d85d13a8c 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php
@@ -309,7 +309,7 @@ public function getFile()
     /**
      * Sets file
      *
-     * @param \OpenAPI\Client\Model\File $file file
+     * @param \OpenAPI\Client\Model\File|null $file file
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getFiles()
     /**
      * Sets files
      *
-     * @param \OpenAPI\Client\Model\File[] $files files
+     * @param \OpenAPI\Client\Model\File[]|null $files files
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php
index b9d98eac6810..dd5e0dff42a0 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php
@@ -302,7 +302,7 @@ public function getBar()
     /**
      * Sets bar
      *
-     * @param string $bar bar
+     * @param string|null $bar bar
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FooGetDefaultResponse.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FooGetDefaultResponse.php
index 16a23acd2757..3d07c5ca3588 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FooGetDefaultResponse.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FooGetDefaultResponse.php
@@ -302,7 +302,7 @@ public function getString()
     /**
      * Sets string
      *
-     * @param \OpenAPI\Client\Model\Foo $string string
+     * @param \OpenAPI\Client\Model\Foo|null $string string
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php
index a902329170a7..4adaf41d13f0 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php
@@ -479,7 +479,7 @@ public function getInteger()
     /**
      * Sets integer
      *
-     * @param int $integer integer
+     * @param int|null $integer integer
      *
      * @return self
      */
@@ -514,7 +514,7 @@ public function getInt32()
     /**
      * Sets int32
      *
-     * @param int $int32 int32
+     * @param int|null $int32 int32
      *
      * @return self
      */
@@ -549,7 +549,7 @@ public function getInt64()
     /**
      * Sets int64
      *
-     * @param int $int64 int64
+     * @param int|null $int64 int64
      *
      * @return self
      */
@@ -611,7 +611,7 @@ public function getFloat()
     /**
      * Sets float
      *
-     * @param float $float float
+     * @param float|null $float float
      *
      * @return self
      */
@@ -646,7 +646,7 @@ public function getDouble()
     /**
      * Sets double
      *
-     * @param float $double double
+     * @param float|null $double double
      *
      * @return self
      */
@@ -681,7 +681,7 @@ public function getDecimal()
     /**
      * Sets decimal
      *
-     * @param float $decimal decimal
+     * @param float|null $decimal decimal
      *
      * @return self
      */
@@ -708,7 +708,7 @@ public function getString()
     /**
      * Sets string
      *
-     * @param string $string string
+     * @param string|null $string string
      *
      * @return self
      */
@@ -767,7 +767,7 @@ public function getBinary()
     /**
      * Sets binary
      *
-     * @param \SplFileObject $binary binary
+     * @param \SplFileObject|null $binary binary
      *
      * @return self
      */
@@ -821,7 +821,7 @@ public function getDateTime()
     /**
      * Sets date_time
      *
-     * @param \DateTime $date_time date_time
+     * @param \DateTime|null $date_time date_time
      *
      * @return self
      */
@@ -848,7 +848,7 @@ public function getUuid()
     /**
      * Sets uuid
      *
-     * @param string $uuid uuid
+     * @param string|null $uuid uuid
      *
      * @return self
      */
@@ -909,7 +909,7 @@ public function getPatternWithDigits()
     /**
      * Sets pattern_with_digits
      *
-     * @param string $pattern_with_digits A string that is a 10 digit number. Can have leading zeros.
+     * @param string|null $pattern_with_digits A string that is a 10 digit number. Can have leading zeros.
      *
      * @return self
      */
@@ -941,7 +941,7 @@ public function getPatternWithDigitsAndDelimiter()
     /**
      * Sets pattern_with_digits_and_delimiter
      *
-     * @param string $pattern_with_digits_and_delimiter A string starting with 'image_' (case insensitive) and one to three digits following i.e. Image_01.
+     * @param string|null $pattern_with_digits_and_delimiter A string starting with 'image_' (case insensitive) and one to three digits following i.e. Image_01.
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php
index 5363669ac934..c56572870ef6 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php
@@ -309,7 +309,7 @@ public function getBar()
     /**
      * Sets bar
      *
-     * @param string $bar bar
+     * @param string|null $bar bar
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getFoo()
     /**
      * Sets foo
      *
-     * @param string $foo foo
+     * @param string|null $foo foo
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php
index bd3b555c917e..b071f434d562 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php
@@ -338,7 +338,7 @@ public function getMapMapOfString()
     /**
      * Sets map_map_of_string
      *
-     * @param array<string,array<string,string>> $map_map_of_string map_map_of_string
+     * @param array<string,array<string,string>>|null $map_map_of_string map_map_of_string
      *
      * @return self
      */
@@ -365,7 +365,7 @@ public function getMapOfEnumString()
     /**
      * Sets map_of_enum_string
      *
-     * @param array<string,string> $map_of_enum_string map_of_enum_string
+     * @param array<string,string>|null $map_of_enum_string map_of_enum_string
      *
      * @return self
      */
@@ -401,7 +401,7 @@ public function getDirectMap()
     /**
      * Sets direct_map
      *
-     * @param array<string,bool> $direct_map direct_map
+     * @param array<string,bool>|null $direct_map direct_map
      *
      * @return self
      */
@@ -428,7 +428,7 @@ public function getIndirectMap()
     /**
      * Sets indirect_map
      *
-     * @param array<string,bool> $indirect_map indirect_map
+     * @param array<string,bool>|null $indirect_map indirect_map
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
index 8bc4281fce4f..b0cbfe7eff29 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
@@ -316,7 +316,7 @@ public function getUuid()
     /**
      * Sets uuid
      *
-     * @param string $uuid uuid
+     * @param string|null $uuid uuid
      *
      * @return self
      */
@@ -343,7 +343,7 @@ public function getDateTime()
     /**
      * Sets date_time
      *
-     * @param \DateTime $date_time date_time
+     * @param \DateTime|null $date_time date_time
      *
      * @return self
      */
@@ -370,7 +370,7 @@ public function getMap()
     /**
      * Sets map
      *
-     * @param array<string,\OpenAPI\Client\Model\Animal> $map map
+     * @param array<string,\OpenAPI\Client\Model\Animal>|null $map map
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php
index d6318fe20e43..87841bba4980 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php
@@ -310,7 +310,7 @@ public function getName()
     /**
      * Sets name
      *
-     * @param int $name name
+     * @param int|null $name name
      *
      * @return self
      */
@@ -337,7 +337,7 @@ public function getClass()
     /**
      * Sets class
      *
-     * @param string $class class
+     * @param string|null $class class
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php
index 67a20b9934e4..7bfcfe28938d 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php
@@ -302,7 +302,7 @@ public function get123List()
     /**
      * Sets _123_list
      *
-     * @param string $_123_list _123_list
+     * @param string|null $_123_list _123_list
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php
index 4257894e8a6e..36672e944716 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php
@@ -303,7 +303,7 @@ public function getReturn()
     /**
      * Sets return
      *
-     * @param int $return return
+     * @param int|null $return return
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php
index 76a367f99b63..b017918420a1 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php
@@ -354,7 +354,7 @@ public function getSnakeCase()
     /**
      * Sets snake_case
      *
-     * @param int $snake_case snake_case
+     * @param int|null $snake_case snake_case
      *
      * @return self
      */
@@ -381,7 +381,7 @@ public function getProperty()
     /**
      * Sets property
      *
-     * @param string $property property
+     * @param string|null $property property
      *
      * @return self
      */
@@ -408,7 +408,7 @@ public function get123Number()
     /**
      * Sets _123_number
      *
-     * @param int $_123_number _123_number
+     * @param int|null $_123_number _123_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php
index f1b10c2a9093..5606e0a85374 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php
@@ -651,7 +651,7 @@ public function getArrayItemsNullable()
     /**
      * Sets array_items_nullable
      *
-     * @param object[] $array_items_nullable array_items_nullable
+     * @param object[]|null $array_items_nullable array_items_nullable
      *
      * @return self
      */
@@ -746,7 +746,7 @@ public function getObjectItemsNullable()
     /**
      * Sets object_items_nullable
      *
-     * @param array<string,object> $object_items_nullable object_items_nullable
+     * @param array<string,object>|null $object_items_nullable object_items_nullable
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php
index 3a3af18bdbed..c937da1a0a8c 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php
@@ -302,7 +302,7 @@ public function getJustNumber()
     /**
      * Sets just_number
      *
-     * @param float $just_number just_number
+     * @param float|null $just_number just_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ObjectWithDeprecatedFields.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ObjectWithDeprecatedFields.php
index c2d43ff5ad76..fe754df399d0 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ObjectWithDeprecatedFields.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ObjectWithDeprecatedFields.php
@@ -323,7 +323,7 @@ public function getUuid()
     /**
      * Sets uuid
      *
-     * @param string $uuid uuid
+     * @param string|null $uuid uuid
      *
      * @return self
      */
@@ -351,7 +351,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param float $id id
+     * @param float|null $id id
      *
      * @return self
      * @deprecated
@@ -380,7 +380,7 @@ public function getDeprecatedRef()
     /**
      * Sets deprecated_ref
      *
-     * @param \OpenAPI\Client\Model\DeprecatedObject $deprecated_ref deprecated_ref
+     * @param \OpenAPI\Client\Model\DeprecatedObject|null $deprecated_ref deprecated_ref
      *
      * @return self
      * @deprecated
@@ -409,7 +409,7 @@ public function getBars()
     /**
      * Sets bars
      *
-     * @param string[] $bars bars
+     * @param string[]|null $bars bars
      *
      * @return self
      * @deprecated
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php
index 8fd6d4e47fe1..e32a3d6bbd33 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php
@@ -363,7 +363,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -390,7 +390,7 @@ public function getPetId()
     /**
      * Sets pet_id
      *
-     * @param int $pet_id pet_id
+     * @param int|null $pet_id pet_id
      *
      * @return self
      */
@@ -417,7 +417,7 @@ public function getQuantity()
     /**
      * Sets quantity
      *
-     * @param int $quantity quantity
+     * @param int|null $quantity quantity
      *
      * @return self
      */
@@ -444,7 +444,7 @@ public function getShipDate()
     /**
      * Sets ship_date
      *
-     * @param \DateTime $ship_date ship_date
+     * @param \DateTime|null $ship_date ship_date
      *
      * @return self
      */
@@ -471,7 +471,7 @@ public function getStatus()
     /**
      * Sets status
      *
-     * @param string $status Order Status
+     * @param string|null $status Order Status
      *
      * @return self
      */
@@ -508,7 +508,7 @@ public function getComplete()
     /**
      * Sets complete
      *
-     * @param bool $complete complete
+     * @param bool|null $complete complete
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php
index 7c5f07f9262a..807f92783b2c 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php
@@ -316,7 +316,7 @@ public function getMyNumber()
     /**
      * Sets my_number
      *
-     * @param float $my_number my_number
+     * @param float|null $my_number my_number
      *
      * @return self
      */
@@ -343,7 +343,7 @@ public function getMyString()
     /**
      * Sets my_string
      *
-     * @param string $my_string my_string
+     * @param string|null $my_string my_string
      *
      * @return self
      */
@@ -370,7 +370,7 @@ public function getMyBoolean()
     /**
      * Sets my_boolean
      *
-     * @param bool $my_boolean my_boolean
+     * @param bool|null $my_boolean my_boolean
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php
index 96ecfe536032..686614ce575a 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php
@@ -369,7 +369,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -396,7 +396,7 @@ public function getCategory()
     /**
      * Sets category
      *
-     * @param \OpenAPI\Client\Model\Category $category category
+     * @param \OpenAPI\Client\Model\Category|null $category category
      *
      * @return self
      */
@@ -479,7 +479,7 @@ public function getTags()
     /**
      * Sets tags
      *
-     * @param \OpenAPI\Client\Model\Tag[] $tags tags
+     * @param \OpenAPI\Client\Model\Tag[]|null $tags tags
      *
      * @return self
      */
@@ -506,7 +506,7 @@ public function getStatus()
     /**
      * Sets status
      *
-     * @param string $status pet status in the store
+     * @param string|null $status pet status in the store
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PetWithFile.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PetWithFile.php
index dafcb8dc3945..ebe95ebdd27d 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PetWithFile.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PetWithFile.php
@@ -383,7 +383,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -410,7 +410,7 @@ public function getCategory()
     /**
      * Sets category
      *
-     * @param \OpenAPI\Client\Model\Category $category category
+     * @param \OpenAPI\Client\Model\Category|null $category category
      *
      * @return self
      */
@@ -493,7 +493,7 @@ public function getTags()
     /**
      * Sets tags
      *
-     * @param \OpenAPI\Client\Model\Tag[] $tags tags
+     * @param \OpenAPI\Client\Model\Tag[]|null $tags tags
      *
      * @return self
      */
@@ -520,7 +520,7 @@ public function getStatus()
     /**
      * Sets status
      *
-     * @param string $status pet status in the store
+     * @param string|null $status pet status in the store
      *
      * @return self
      */
@@ -557,7 +557,7 @@ public function getFile()
     /**
      * Sets file
      *
-     * @param \SplFileObject $file file to upload
+     * @param \SplFileObject|null $file file to upload
      *
      * @return self
      */
@@ -584,7 +584,7 @@ public function getMultipleFiles()
     /**
      * Sets multiple_files
      *
-     * @param \SplFileObject[] $multiple_files multiple_files
+     * @param \SplFileObject[]|null $multiple_files multiple_files
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PropertyNameMapping.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PropertyNameMapping.php
index ab75bb7ff659..03c19655e4aa 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PropertyNameMapping.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/PropertyNameMapping.php
@@ -323,7 +323,7 @@ public function getHttpDebugOperation()
     /**
      * Sets http_debug_operation
      *
-     * @param string $http_debug_operation http_debug_operation
+     * @param string|null $http_debug_operation http_debug_operation
      *
      * @return self
      */
@@ -350,7 +350,7 @@ public function getUnderscoreType()
     /**
      * Sets underscore_type
      *
-     * @param string $underscore_type underscore_type
+     * @param string|null $underscore_type underscore_type
      *
      * @return self
      */
@@ -377,7 +377,7 @@ public function getType()
     /**
      * Sets type
      *
-     * @param string $type type
+     * @param string|null $type type
      *
      * @return self
      */
@@ -404,7 +404,7 @@ public function getTypeWithUnderscore()
     /**
      * Sets type_with_underscore
      *
-     * @param string $type_with_underscore type_with_underscore
+     * @param string|null $type_with_underscore type_with_underscore
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php
index 4a55162bf197..282f272cf0e8 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php
@@ -309,7 +309,7 @@ public function getBar()
     /**
      * Sets bar
      *
-     * @param string $bar bar
+     * @param string|null $bar bar
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getBaz()
     /**
      * Sets baz
      *
-     * @param string $baz baz
+     * @param string|null $baz baz
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php
index 9eaf5b46986d..d69edd2ed1ba 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php
@@ -302,7 +302,7 @@ public function getSpecialPropertyName()
     /**
      * Sets special_property_name
      *
-     * @param int $special_property_name special_property_name
+     * @param int|null $special_property_name special_property_name
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php
index 3fd14123c238..3ebdcdb89269 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php
@@ -309,7 +309,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getName()
     /**
      * Sets name
      *
-     * @param string $name name
+     * @param string|null $name name
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php
index 84503dee9784..8c06333caca8 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php
@@ -302,7 +302,7 @@ public function getSomeProperty()
     /**
      * Sets some_property
      *
-     * @param string $some_property some_property
+     * @param string|null $some_property some_property
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php
index 8f937e60ef34..2922da586c54 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php
@@ -351,7 +351,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -378,7 +378,7 @@ public function getUsername()
     /**
      * Sets username
      *
-     * @param string $username username
+     * @param string|null $username username
      *
      * @return self
      */
@@ -405,7 +405,7 @@ public function getFirstName()
     /**
      * Sets first_name
      *
-     * @param string $first_name first_name
+     * @param string|null $first_name first_name
      *
      * @return self
      */
@@ -432,7 +432,7 @@ public function getLastName()
     /**
      * Sets last_name
      *
-     * @param string $last_name last_name
+     * @param string|null $last_name last_name
      *
      * @return self
      */
@@ -459,7 +459,7 @@ public function getEmail()
     /**
      * Sets email
      *
-     * @param string $email email
+     * @param string|null $email email
      *
      * @return self
      */
@@ -486,7 +486,7 @@ public function getPassword()
     /**
      * Sets password
      *
-     * @param string $password password
+     * @param string|null $password password
      *
      * @return self
      */
@@ -513,7 +513,7 @@ public function getPhone()
     /**
      * Sets phone
      *
-     * @param string $phone phone
+     * @param string|null $phone phone
      *
      * @return self
      */
@@ -540,7 +540,7 @@ public function getUserStatus()
     /**
      * Sets user_status
      *
-     * @param int $user_status User Status
+     * @param int|null $user_status User Status
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/AdditionalPropertiesClass.php b/samples/client/petstore/php/psr-18/lib/Model/AdditionalPropertiesClass.php
index ecc9f2b000ad..7b1d78543379 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/AdditionalPropertiesClass.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/AdditionalPropertiesClass.php
@@ -309,7 +309,7 @@ public function getMapProperty()
     /**
      * Sets map_property
      *
-     * @param array<string,string> $map_property map_property
+     * @param array<string,string>|null $map_property map_property
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getMapOfMapProperty()
     /**
      * Sets map_of_map_property
      *
-     * @param array<string,array<string,string>> $map_of_map_property map_of_map_property
+     * @param array<string,array<string,string>>|null $map_of_map_property map_of_map_property
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/AllOfWithSingleRef.php b/samples/client/petstore/php/psr-18/lib/Model/AllOfWithSingleRef.php
index 3c3a1a9bfc88..a198a937a5ba 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/AllOfWithSingleRef.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/AllOfWithSingleRef.php
@@ -309,7 +309,7 @@ public function getUsername()
     /**
      * Sets username
      *
-     * @param string $username username
+     * @param string|null $username username
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getSingleRefType()
     /**
      * Sets single_ref_type
      *
-     * @param \OpenAPI\Client\Model\SingleRefType $single_ref_type single_ref_type
+     * @param \OpenAPI\Client\Model\SingleRefType|null $single_ref_type single_ref_type
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Animal.php b/samples/client/petstore/php/psr-18/lib/Model/Animal.php
index a03b0faa840c..ff733fda6512 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Animal.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Animal.php
@@ -342,7 +342,7 @@ public function getColor()
     /**
      * Sets color
      *
-     * @param string $color color
+     * @param string|null $color color
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ApiResponse.php b/samples/client/petstore/php/psr-18/lib/Model/ApiResponse.php
index a8a4a7682bf7..f0999711bbbe 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ApiResponse.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ApiResponse.php
@@ -316,7 +316,7 @@ public function getCode()
     /**
      * Sets code
      *
-     * @param int $code code
+     * @param int|null $code code
      *
      * @return self
      */
@@ -343,7 +343,7 @@ public function getType()
     /**
      * Sets type
      *
-     * @param string $type type
+     * @param string|null $type type
      *
      * @return self
      */
@@ -370,7 +370,7 @@ public function getMessage()
     /**
      * Sets message
      *
-     * @param string $message message
+     * @param string|null $message message
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ArrayOfArrayOfNumberOnly.php b/samples/client/petstore/php/psr-18/lib/Model/ArrayOfArrayOfNumberOnly.php
index bef6d5bdfc0e..2be31050ba4a 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ArrayOfArrayOfNumberOnly.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ArrayOfArrayOfNumberOnly.php
@@ -302,7 +302,7 @@ public function getArrayArrayNumber()
     /**
      * Sets array_array_number
      *
-     * @param float[][] $array_array_number array_array_number
+     * @param float[][]|null $array_array_number array_array_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ArrayOfNumberOnly.php b/samples/client/petstore/php/psr-18/lib/Model/ArrayOfNumberOnly.php
index 9a9e9c4cb70e..83db4149ab65 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ArrayOfNumberOnly.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ArrayOfNumberOnly.php
@@ -302,7 +302,7 @@ public function getArrayNumber()
     /**
      * Sets array_number
      *
-     * @param float[] $array_number array_number
+     * @param float[]|null $array_number array_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ArrayTest.php b/samples/client/petstore/php/psr-18/lib/Model/ArrayTest.php
index ba7df9ff7379..7b68751714a4 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ArrayTest.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ArrayTest.php
@@ -324,7 +324,7 @@ public function getArrayOfString()
     /**
      * Sets array_of_string
      *
-     * @param string[] $array_of_string array_of_string
+     * @param string[]|null $array_of_string array_of_string
      *
      * @return self
      */
@@ -358,7 +358,7 @@ public function getArrayArrayOfInteger()
     /**
      * Sets array_array_of_integer
      *
-     * @param int[][] $array_array_of_integer array_array_of_integer
+     * @param int[][]|null $array_array_of_integer array_array_of_integer
      *
      * @return self
      */
@@ -385,7 +385,7 @@ public function getArrayArrayOfModel()
     /**
      * Sets array_array_of_model
      *
-     * @param \OpenAPI\Client\Model\ReadOnlyFirst[][] $array_array_of_model array_array_of_model
+     * @param \OpenAPI\Client\Model\ReadOnlyFirst[][]|null $array_array_of_model array_array_of_model
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Capitalization.php b/samples/client/petstore/php/psr-18/lib/Model/Capitalization.php
index 5bd9fe1b6670..3204141d9263 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Capitalization.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Capitalization.php
@@ -337,7 +337,7 @@ public function getSmallCamel()
     /**
      * Sets small_camel
      *
-     * @param string $small_camel small_camel
+     * @param string|null $small_camel small_camel
      *
      * @return self
      */
@@ -364,7 +364,7 @@ public function getCapitalCamel()
     /**
      * Sets capital_camel
      *
-     * @param string $capital_camel capital_camel
+     * @param string|null $capital_camel capital_camel
      *
      * @return self
      */
@@ -391,7 +391,7 @@ public function getSmallSnake()
     /**
      * Sets small_snake
      *
-     * @param string $small_snake small_snake
+     * @param string|null $small_snake small_snake
      *
      * @return self
      */
@@ -418,7 +418,7 @@ public function getCapitalSnake()
     /**
      * Sets capital_snake
      *
-     * @param string $capital_snake capital_snake
+     * @param string|null $capital_snake capital_snake
      *
      * @return self
      */
@@ -445,7 +445,7 @@ public function getScaEthFlowPoints()
     /**
      * Sets sca_eth_flow_points
      *
-     * @param string $sca_eth_flow_points sca_eth_flow_points
+     * @param string|null $sca_eth_flow_points sca_eth_flow_points
      *
      * @return self
      */
@@ -472,7 +472,7 @@ public function getAttName()
     /**
      * Sets att_name
      *
-     * @param string $att_name Name of the pet
+     * @param string|null $att_name Name of the pet
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Cat.php b/samples/client/petstore/php/psr-18/lib/Model/Cat.php
index 13b65964a256..80c58c4b584e 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Cat.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Cat.php
@@ -296,7 +296,7 @@ public function getDeclawed()
     /**
      * Sets declawed
      *
-     * @param bool $declawed declawed
+     * @param bool|null $declawed declawed
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Category.php b/samples/client/petstore/php/psr-18/lib/Model/Category.php
index 4d953336f5b0..7397c09d5546 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Category.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Category.php
@@ -312,7 +312,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ClassModel.php b/samples/client/petstore/php/psr-18/lib/Model/ClassModel.php
index 9a9b24087484..373bbdc6225f 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ClassModel.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ClassModel.php
@@ -303,7 +303,7 @@ public function getClass()
     /**
      * Sets _class
      *
-     * @param string $_class _class
+     * @param string|null $_class _class
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Client.php b/samples/client/petstore/php/psr-18/lib/Model/Client.php
index a5dc5538b192..29699d28b0d8 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Client.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Client.php
@@ -302,7 +302,7 @@ public function getClient()
     /**
      * Sets client
      *
-     * @param string $client client
+     * @param string|null $client client
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/DeprecatedObject.php b/samples/client/petstore/php/psr-18/lib/Model/DeprecatedObject.php
index fb82b38d25c5..46c011375d64 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/DeprecatedObject.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/DeprecatedObject.php
@@ -302,7 +302,7 @@ public function getName()
     /**
      * Sets name
      *
-     * @param string $name name
+     * @param string|null $name name
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Dog.php b/samples/client/petstore/php/psr-18/lib/Model/Dog.php
index b6f90c3bd183..58890d772e13 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Dog.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Dog.php
@@ -296,7 +296,7 @@ public function getBreed()
     /**
      * Sets breed
      *
-     * @param string $breed breed
+     * @param string|null $breed breed
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/EnumArrays.php b/samples/client/petstore/php/psr-18/lib/Model/EnumArrays.php
index 7711c0ba6a10..b5c179f6a170 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/EnumArrays.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/EnumArrays.php
@@ -348,7 +348,7 @@ public function getJustSymbol()
     /**
      * Sets just_symbol
      *
-     * @param string $just_symbol just_symbol
+     * @param string|null $just_symbol just_symbol
      *
      * @return self
      */
@@ -385,7 +385,7 @@ public function getArrayEnum()
     /**
      * Sets array_enum
      *
-     * @param string[] $array_enum array_enum
+     * @param string[]|null $array_enum array_enum
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/EnumTest.php b/samples/client/petstore/php/psr-18/lib/Model/EnumTest.php
index 1965d18994cf..6f863a21ac86 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/EnumTest.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/EnumTest.php
@@ -454,7 +454,7 @@ public function getEnumString()
     /**
      * Sets enum_string
      *
-     * @param string $enum_string enum_string
+     * @param string|null $enum_string enum_string
      *
      * @return self
      */
@@ -528,7 +528,7 @@ public function getEnumInteger()
     /**
      * Sets enum_integer
      *
-     * @param int $enum_integer enum_integer
+     * @param int|null $enum_integer enum_integer
      *
      * @return self
      */
@@ -565,7 +565,7 @@ public function getEnumNumber()
     /**
      * Sets enum_number
      *
-     * @param float $enum_number enum_number
+     * @param float|null $enum_number enum_number
      *
      * @return self
      */
@@ -636,7 +636,7 @@ public function getOuterEnumInteger()
     /**
      * Sets outer_enum_integer
      *
-     * @param \OpenAPI\Client\Model\OuterEnumInteger $outer_enum_integer outer_enum_integer
+     * @param \OpenAPI\Client\Model\OuterEnumInteger|null $outer_enum_integer outer_enum_integer
      *
      * @return self
      */
@@ -663,7 +663,7 @@ public function getOuterEnumDefaultValue()
     /**
      * Sets outer_enum_default_value
      *
-     * @param \OpenAPI\Client\Model\OuterEnumDefaultValue $outer_enum_default_value outer_enum_default_value
+     * @param \OpenAPI\Client\Model\OuterEnumDefaultValue|null $outer_enum_default_value outer_enum_default_value
      *
      * @return self
      */
@@ -690,7 +690,7 @@ public function getOuterEnumIntegerDefaultValue()
     /**
      * Sets outer_enum_integer_default_value
      *
-     * @param \OpenAPI\Client\Model\OuterEnumIntegerDefaultValue $outer_enum_integer_default_value outer_enum_integer_default_value
+     * @param \OpenAPI\Client\Model\OuterEnumIntegerDefaultValue|null $outer_enum_integer_default_value outer_enum_integer_default_value
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ErrorResponse.php b/samples/client/petstore/php/psr-18/lib/Model/ErrorResponse.php
index 320272b436b0..e036cf0ae754 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ErrorResponse.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ErrorResponse.php
@@ -309,7 +309,7 @@ public function getResponseCode()
     /**
      * Sets response_code
      *
-     * @param int $response_code response_code
+     * @param int|null $response_code response_code
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getError()
     /**
      * Sets error
      *
-     * @param string $error error
+     * @param string|null $error error
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/FakeBigDecimalMap200Response.php b/samples/client/petstore/php/psr-18/lib/Model/FakeBigDecimalMap200Response.php
index de2e8dda7cd9..4db0ab564ba7 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/FakeBigDecimalMap200Response.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/FakeBigDecimalMap200Response.php
@@ -309,7 +309,7 @@ public function getSomeId()
     /**
      * Sets some_id
      *
-     * @param float $some_id some_id
+     * @param float|null $some_id some_id
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getSomeMap()
     /**
      * Sets some_map
      *
-     * @param array<string,float> $some_map some_map
+     * @param array<string,float>|null $some_map some_map
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/File.php b/samples/client/petstore/php/psr-18/lib/Model/File.php
index f643a577f0fb..c44266813d92 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/File.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/File.php
@@ -303,7 +303,7 @@ public function getSourceUri()
     /**
      * Sets source_uri
      *
-     * @param string $source_uri Test capitalization
+     * @param string|null $source_uri Test capitalization
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/FileSchemaTestClass.php b/samples/client/petstore/php/psr-18/lib/Model/FileSchemaTestClass.php
index 5c79651aaf64..b68d85d13a8c 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/FileSchemaTestClass.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/FileSchemaTestClass.php
@@ -309,7 +309,7 @@ public function getFile()
     /**
      * Sets file
      *
-     * @param \OpenAPI\Client\Model\File $file file
+     * @param \OpenAPI\Client\Model\File|null $file file
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getFiles()
     /**
      * Sets files
      *
-     * @param \OpenAPI\Client\Model\File[] $files files
+     * @param \OpenAPI\Client\Model\File[]|null $files files
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Foo.php b/samples/client/petstore/php/psr-18/lib/Model/Foo.php
index b9d98eac6810..dd5e0dff42a0 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Foo.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Foo.php
@@ -302,7 +302,7 @@ public function getBar()
     /**
      * Sets bar
      *
-     * @param string $bar bar
+     * @param string|null $bar bar
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/FooGetDefaultResponse.php b/samples/client/petstore/php/psr-18/lib/Model/FooGetDefaultResponse.php
index 16a23acd2757..3d07c5ca3588 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/FooGetDefaultResponse.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/FooGetDefaultResponse.php
@@ -302,7 +302,7 @@ public function getString()
     /**
      * Sets string
      *
-     * @param \OpenAPI\Client\Model\Foo $string string
+     * @param \OpenAPI\Client\Model\Foo|null $string string
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/FormatTest.php b/samples/client/petstore/php/psr-18/lib/Model/FormatTest.php
index a902329170a7..4adaf41d13f0 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/FormatTest.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/FormatTest.php
@@ -479,7 +479,7 @@ public function getInteger()
     /**
      * Sets integer
      *
-     * @param int $integer integer
+     * @param int|null $integer integer
      *
      * @return self
      */
@@ -514,7 +514,7 @@ public function getInt32()
     /**
      * Sets int32
      *
-     * @param int $int32 int32
+     * @param int|null $int32 int32
      *
      * @return self
      */
@@ -549,7 +549,7 @@ public function getInt64()
     /**
      * Sets int64
      *
-     * @param int $int64 int64
+     * @param int|null $int64 int64
      *
      * @return self
      */
@@ -611,7 +611,7 @@ public function getFloat()
     /**
      * Sets float
      *
-     * @param float $float float
+     * @param float|null $float float
      *
      * @return self
      */
@@ -646,7 +646,7 @@ public function getDouble()
     /**
      * Sets double
      *
-     * @param float $double double
+     * @param float|null $double double
      *
      * @return self
      */
@@ -681,7 +681,7 @@ public function getDecimal()
     /**
      * Sets decimal
      *
-     * @param float $decimal decimal
+     * @param float|null $decimal decimal
      *
      * @return self
      */
@@ -708,7 +708,7 @@ public function getString()
     /**
      * Sets string
      *
-     * @param string $string string
+     * @param string|null $string string
      *
      * @return self
      */
@@ -767,7 +767,7 @@ public function getBinary()
     /**
      * Sets binary
      *
-     * @param \SplFileObject $binary binary
+     * @param \SplFileObject|null $binary binary
      *
      * @return self
      */
@@ -821,7 +821,7 @@ public function getDateTime()
     /**
      * Sets date_time
      *
-     * @param \DateTime $date_time date_time
+     * @param \DateTime|null $date_time date_time
      *
      * @return self
      */
@@ -848,7 +848,7 @@ public function getUuid()
     /**
      * Sets uuid
      *
-     * @param string $uuid uuid
+     * @param string|null $uuid uuid
      *
      * @return self
      */
@@ -909,7 +909,7 @@ public function getPatternWithDigits()
     /**
      * Sets pattern_with_digits
      *
-     * @param string $pattern_with_digits A string that is a 10 digit number. Can have leading zeros.
+     * @param string|null $pattern_with_digits A string that is a 10 digit number. Can have leading zeros.
      *
      * @return self
      */
@@ -941,7 +941,7 @@ public function getPatternWithDigitsAndDelimiter()
     /**
      * Sets pattern_with_digits_and_delimiter
      *
-     * @param string $pattern_with_digits_and_delimiter A string starting with 'image_' (case insensitive) and one to three digits following i.e. Image_01.
+     * @param string|null $pattern_with_digits_and_delimiter A string starting with 'image_' (case insensitive) and one to three digits following i.e. Image_01.
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/HasOnlyReadOnly.php b/samples/client/petstore/php/psr-18/lib/Model/HasOnlyReadOnly.php
index 5363669ac934..c56572870ef6 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/HasOnlyReadOnly.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/HasOnlyReadOnly.php
@@ -309,7 +309,7 @@ public function getBar()
     /**
      * Sets bar
      *
-     * @param string $bar bar
+     * @param string|null $bar bar
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getFoo()
     /**
      * Sets foo
      *
-     * @param string $foo foo
+     * @param string|null $foo foo
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/MapTest.php b/samples/client/petstore/php/psr-18/lib/Model/MapTest.php
index bd3b555c917e..b071f434d562 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/MapTest.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/MapTest.php
@@ -338,7 +338,7 @@ public function getMapMapOfString()
     /**
      * Sets map_map_of_string
      *
-     * @param array<string,array<string,string>> $map_map_of_string map_map_of_string
+     * @param array<string,array<string,string>>|null $map_map_of_string map_map_of_string
      *
      * @return self
      */
@@ -365,7 +365,7 @@ public function getMapOfEnumString()
     /**
      * Sets map_of_enum_string
      *
-     * @param array<string,string> $map_of_enum_string map_of_enum_string
+     * @param array<string,string>|null $map_of_enum_string map_of_enum_string
      *
      * @return self
      */
@@ -401,7 +401,7 @@ public function getDirectMap()
     /**
      * Sets direct_map
      *
-     * @param array<string,bool> $direct_map direct_map
+     * @param array<string,bool>|null $direct_map direct_map
      *
      * @return self
      */
@@ -428,7 +428,7 @@ public function getIndirectMap()
     /**
      * Sets indirect_map
      *
-     * @param array<string,bool> $indirect_map indirect_map
+     * @param array<string,bool>|null $indirect_map indirect_map
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php b/samples/client/petstore/php/psr-18/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
index 8bc4281fce4f..b0cbfe7eff29 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
@@ -316,7 +316,7 @@ public function getUuid()
     /**
      * Sets uuid
      *
-     * @param string $uuid uuid
+     * @param string|null $uuid uuid
      *
      * @return self
      */
@@ -343,7 +343,7 @@ public function getDateTime()
     /**
      * Sets date_time
      *
-     * @param \DateTime $date_time date_time
+     * @param \DateTime|null $date_time date_time
      *
      * @return self
      */
@@ -370,7 +370,7 @@ public function getMap()
     /**
      * Sets map
      *
-     * @param array<string,\OpenAPI\Client\Model\Animal> $map map
+     * @param array<string,\OpenAPI\Client\Model\Animal>|null $map map
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Model200Response.php b/samples/client/petstore/php/psr-18/lib/Model/Model200Response.php
index d6318fe20e43..87841bba4980 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Model200Response.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Model200Response.php
@@ -310,7 +310,7 @@ public function getName()
     /**
      * Sets name
      *
-     * @param int $name name
+     * @param int|null $name name
      *
      * @return self
      */
@@ -337,7 +337,7 @@ public function getClass()
     /**
      * Sets class
      *
-     * @param string $class class
+     * @param string|null $class class
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ModelList.php b/samples/client/petstore/php/psr-18/lib/Model/ModelList.php
index 67a20b9934e4..7bfcfe28938d 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ModelList.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ModelList.php
@@ -302,7 +302,7 @@ public function get123List()
     /**
      * Sets _123_list
      *
-     * @param string $_123_list _123_list
+     * @param string|null $_123_list _123_list
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ModelReturn.php b/samples/client/petstore/php/psr-18/lib/Model/ModelReturn.php
index 4257894e8a6e..36672e944716 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ModelReturn.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ModelReturn.php
@@ -303,7 +303,7 @@ public function getReturn()
     /**
      * Sets return
      *
-     * @param int $return return
+     * @param int|null $return return
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Name.php b/samples/client/petstore/php/psr-18/lib/Model/Name.php
index 76a367f99b63..b017918420a1 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Name.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Name.php
@@ -354,7 +354,7 @@ public function getSnakeCase()
     /**
      * Sets snake_case
      *
-     * @param int $snake_case snake_case
+     * @param int|null $snake_case snake_case
      *
      * @return self
      */
@@ -381,7 +381,7 @@ public function getProperty()
     /**
      * Sets property
      *
-     * @param string $property property
+     * @param string|null $property property
      *
      * @return self
      */
@@ -408,7 +408,7 @@ public function get123Number()
     /**
      * Sets _123_number
      *
-     * @param int $_123_number _123_number
+     * @param int|null $_123_number _123_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/NullableClass.php b/samples/client/petstore/php/psr-18/lib/Model/NullableClass.php
index f1b10c2a9093..5606e0a85374 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/NullableClass.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/NullableClass.php
@@ -651,7 +651,7 @@ public function getArrayItemsNullable()
     /**
      * Sets array_items_nullable
      *
-     * @param object[] $array_items_nullable array_items_nullable
+     * @param object[]|null $array_items_nullable array_items_nullable
      *
      * @return self
      */
@@ -746,7 +746,7 @@ public function getObjectItemsNullable()
     /**
      * Sets object_items_nullable
      *
-     * @param array<string,object> $object_items_nullable object_items_nullable
+     * @param array<string,object>|null $object_items_nullable object_items_nullable
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/NumberOnly.php b/samples/client/petstore/php/psr-18/lib/Model/NumberOnly.php
index 3a3af18bdbed..c937da1a0a8c 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/NumberOnly.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/NumberOnly.php
@@ -302,7 +302,7 @@ public function getJustNumber()
     /**
      * Sets just_number
      *
-     * @param float $just_number just_number
+     * @param float|null $just_number just_number
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ObjectWithDeprecatedFields.php b/samples/client/petstore/php/psr-18/lib/Model/ObjectWithDeprecatedFields.php
index c2d43ff5ad76..fe754df399d0 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ObjectWithDeprecatedFields.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ObjectWithDeprecatedFields.php
@@ -323,7 +323,7 @@ public function getUuid()
     /**
      * Sets uuid
      *
-     * @param string $uuid uuid
+     * @param string|null $uuid uuid
      *
      * @return self
      */
@@ -351,7 +351,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param float $id id
+     * @param float|null $id id
      *
      * @return self
      * @deprecated
@@ -380,7 +380,7 @@ public function getDeprecatedRef()
     /**
      * Sets deprecated_ref
      *
-     * @param \OpenAPI\Client\Model\DeprecatedObject $deprecated_ref deprecated_ref
+     * @param \OpenAPI\Client\Model\DeprecatedObject|null $deprecated_ref deprecated_ref
      *
      * @return self
      * @deprecated
@@ -409,7 +409,7 @@ public function getBars()
     /**
      * Sets bars
      *
-     * @param string[] $bars bars
+     * @param string[]|null $bars bars
      *
      * @return self
      * @deprecated
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Order.php b/samples/client/petstore/php/psr-18/lib/Model/Order.php
index 8fd6d4e47fe1..e32a3d6bbd33 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Order.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Order.php
@@ -363,7 +363,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -390,7 +390,7 @@ public function getPetId()
     /**
      * Sets pet_id
      *
-     * @param int $pet_id pet_id
+     * @param int|null $pet_id pet_id
      *
      * @return self
      */
@@ -417,7 +417,7 @@ public function getQuantity()
     /**
      * Sets quantity
      *
-     * @param int $quantity quantity
+     * @param int|null $quantity quantity
      *
      * @return self
      */
@@ -444,7 +444,7 @@ public function getShipDate()
     /**
      * Sets ship_date
      *
-     * @param \DateTime $ship_date ship_date
+     * @param \DateTime|null $ship_date ship_date
      *
      * @return self
      */
@@ -471,7 +471,7 @@ public function getStatus()
     /**
      * Sets status
      *
-     * @param string $status Order Status
+     * @param string|null $status Order Status
      *
      * @return self
      */
@@ -508,7 +508,7 @@ public function getComplete()
     /**
      * Sets complete
      *
-     * @param bool $complete complete
+     * @param bool|null $complete complete
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/OuterComposite.php b/samples/client/petstore/php/psr-18/lib/Model/OuterComposite.php
index 7c5f07f9262a..807f92783b2c 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/OuterComposite.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/OuterComposite.php
@@ -316,7 +316,7 @@ public function getMyNumber()
     /**
      * Sets my_number
      *
-     * @param float $my_number my_number
+     * @param float|null $my_number my_number
      *
      * @return self
      */
@@ -343,7 +343,7 @@ public function getMyString()
     /**
      * Sets my_string
      *
-     * @param string $my_string my_string
+     * @param string|null $my_string my_string
      *
      * @return self
      */
@@ -370,7 +370,7 @@ public function getMyBoolean()
     /**
      * Sets my_boolean
      *
-     * @param bool $my_boolean my_boolean
+     * @param bool|null $my_boolean my_boolean
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Pet.php b/samples/client/petstore/php/psr-18/lib/Model/Pet.php
index 96ecfe536032..686614ce575a 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Pet.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Pet.php
@@ -369,7 +369,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -396,7 +396,7 @@ public function getCategory()
     /**
      * Sets category
      *
-     * @param \OpenAPI\Client\Model\Category $category category
+     * @param \OpenAPI\Client\Model\Category|null $category category
      *
      * @return self
      */
@@ -479,7 +479,7 @@ public function getTags()
     /**
      * Sets tags
      *
-     * @param \OpenAPI\Client\Model\Tag[] $tags tags
+     * @param \OpenAPI\Client\Model\Tag[]|null $tags tags
      *
      * @return self
      */
@@ -506,7 +506,7 @@ public function getStatus()
     /**
      * Sets status
      *
-     * @param string $status pet status in the store
+     * @param string|null $status pet status in the store
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/PetWithFile.php b/samples/client/petstore/php/psr-18/lib/Model/PetWithFile.php
index dafcb8dc3945..ebe95ebdd27d 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/PetWithFile.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/PetWithFile.php
@@ -383,7 +383,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -410,7 +410,7 @@ public function getCategory()
     /**
      * Sets category
      *
-     * @param \OpenAPI\Client\Model\Category $category category
+     * @param \OpenAPI\Client\Model\Category|null $category category
      *
      * @return self
      */
@@ -493,7 +493,7 @@ public function getTags()
     /**
      * Sets tags
      *
-     * @param \OpenAPI\Client\Model\Tag[] $tags tags
+     * @param \OpenAPI\Client\Model\Tag[]|null $tags tags
      *
      * @return self
      */
@@ -520,7 +520,7 @@ public function getStatus()
     /**
      * Sets status
      *
-     * @param string $status pet status in the store
+     * @param string|null $status pet status in the store
      *
      * @return self
      */
@@ -557,7 +557,7 @@ public function getFile()
     /**
      * Sets file
      *
-     * @param \SplFileObject $file file to upload
+     * @param \SplFileObject|null $file file to upload
      *
      * @return self
      */
@@ -584,7 +584,7 @@ public function getMultipleFiles()
     /**
      * Sets multiple_files
      *
-     * @param \SplFileObject[] $multiple_files multiple_files
+     * @param \SplFileObject[]|null $multiple_files multiple_files
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/PropertyNameMapping.php b/samples/client/petstore/php/psr-18/lib/Model/PropertyNameMapping.php
index ab75bb7ff659..03c19655e4aa 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/PropertyNameMapping.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/PropertyNameMapping.php
@@ -323,7 +323,7 @@ public function getHttpDebugOperation()
     /**
      * Sets http_debug_operation
      *
-     * @param string $http_debug_operation http_debug_operation
+     * @param string|null $http_debug_operation http_debug_operation
      *
      * @return self
      */
@@ -350,7 +350,7 @@ public function getUnderscoreType()
     /**
      * Sets underscore_type
      *
-     * @param string $underscore_type underscore_type
+     * @param string|null $underscore_type underscore_type
      *
      * @return self
      */
@@ -377,7 +377,7 @@ public function getType()
     /**
      * Sets type
      *
-     * @param string $type type
+     * @param string|null $type type
      *
      * @return self
      */
@@ -404,7 +404,7 @@ public function getTypeWithUnderscore()
     /**
      * Sets type_with_underscore
      *
-     * @param string $type_with_underscore type_with_underscore
+     * @param string|null $type_with_underscore type_with_underscore
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/ReadOnlyFirst.php b/samples/client/petstore/php/psr-18/lib/Model/ReadOnlyFirst.php
index 4a55162bf197..282f272cf0e8 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/ReadOnlyFirst.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/ReadOnlyFirst.php
@@ -309,7 +309,7 @@ public function getBar()
     /**
      * Sets bar
      *
-     * @param string $bar bar
+     * @param string|null $bar bar
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getBaz()
     /**
      * Sets baz
      *
-     * @param string $baz baz
+     * @param string|null $baz baz
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/SpecialModelName.php b/samples/client/petstore/php/psr-18/lib/Model/SpecialModelName.php
index 9eaf5b46986d..d69edd2ed1ba 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/SpecialModelName.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/SpecialModelName.php
@@ -302,7 +302,7 @@ public function getSpecialPropertyName()
     /**
      * Sets special_property_name
      *
-     * @param int $special_property_name special_property_name
+     * @param int|null $special_property_name special_property_name
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/Tag.php b/samples/client/petstore/php/psr-18/lib/Model/Tag.php
index 3fd14123c238..3ebdcdb89269 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/Tag.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/Tag.php
@@ -309,7 +309,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -336,7 +336,7 @@ public function getName()
     /**
      * Sets name
      *
-     * @param string $name name
+     * @param string|null $name name
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php b/samples/client/petstore/php/psr-18/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php
index 84503dee9784..8c06333caca8 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/TestInlineFreeformAdditionalPropertiesRequest.php
@@ -302,7 +302,7 @@ public function getSomeProperty()
     /**
      * Sets some_property
      *
-     * @param string $some_property some_property
+     * @param string|null $some_property some_property
      *
      * @return self
      */
diff --git a/samples/client/petstore/php/psr-18/lib/Model/User.php b/samples/client/petstore/php/psr-18/lib/Model/User.php
index 8f937e60ef34..2922da586c54 100644
--- a/samples/client/petstore/php/psr-18/lib/Model/User.php
+++ b/samples/client/petstore/php/psr-18/lib/Model/User.php
@@ -351,7 +351,7 @@ public function getId()
     /**
      * Sets id
      *
-     * @param int $id id
+     * @param int|null $id id
      *
      * @return self
      */
@@ -378,7 +378,7 @@ public function getUsername()
     /**
      * Sets username
      *
-     * @param string $username username
+     * @param string|null $username username
      *
      * @return self
      */
@@ -405,7 +405,7 @@ public function getFirstName()
     /**
      * Sets first_name
      *
-     * @param string $first_name first_name
+     * @param string|null $first_name first_name
      *
      * @return self
      */
@@ -432,7 +432,7 @@ public function getLastName()
     /**
      * Sets last_name
      *
-     * @param string $last_name last_name
+     * @param string|null $last_name last_name
      *
      * @return self
      */
@@ -459,7 +459,7 @@ public function getEmail()
     /**
      * Sets email
      *
-     * @param string $email email
+     * @param string|null $email email
      *
      * @return self
      */
@@ -486,7 +486,7 @@ public function getPassword()
     /**
      * Sets password
      *
-     * @param string $password password
+     * @param string|null $password password
      *
      * @return self
      */
@@ -513,7 +513,7 @@ public function getPhone()
     /**
      * Sets phone
      *
-     * @param string $phone phone
+     * @param string|null $phone phone
      *
      * @return self
      */
@@ -540,7 +540,7 @@ public function getUserStatus()
     /**
      * Sets user_status
      *
-     * @param int $user_status User Status
+     * @param int|null $user_status User Status
      *
      * @return self
      */