diff --git a/ide-plugin/build.gradle.kts b/ide-plugin/build.gradle.kts
index 62951b0b..aaae5df8 100644
--- a/ide-plugin/build.gradle.kts
+++ b/ide-plugin/build.gradle.kts
@@ -50,8 +50,10 @@ java {
 
 
 tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
-    kotlinOptions.jvmTarget = targetJvm
-    kotlinOptions.apiVersion = "1.4"
+    compilerOptions {
+        jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.fromTarget(targetJvm))
+        apiVersion.set(org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_1_9)
+    }
 }
 
 tasks.getByName("buildSearchableOptions").enabled = false
diff --git a/server/build.gradle.kts b/server/build.gradle.kts
index a359bdb9..17e32b6a 100644
--- a/server/build.gradle.kts
+++ b/server/build.gradle.kts
@@ -26,9 +26,9 @@ java {
 }
 
 tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
-    kotlinOptions {
-        jvmTarget = targetJvm
-        apiVersion = "1.5"
+    compilerOptions {
+        jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.fromTarget(targetJvm))
+        apiVersion.set(org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_1_9)
     }
 }
 
diff --git a/server/src/test/kotlin/cloud/skadi/ApplicationTest.kt b/server/src/test/kotlin/cloud/skadi/ApplicationTest.kt
index b5195118..68d336c1 100644
--- a/server/src/test/kotlin/cloud/skadi/ApplicationTest.kt
+++ b/server/src/test/kotlin/cloud/skadi/ApplicationTest.kt
@@ -20,7 +20,7 @@ class ApplicationTest {
             withTestApplication({ testModuleSetup(dbName) }) {
                 handleRequest(HttpMethod.Get, "/").apply {
                     assertEquals(HttpStatusCode.OK, response.status())
-                    val document = Jsoup.parse(response.content)
+                    val document = Jsoup.parse(response.content!!)
                     val firstLinkInMenu = document.selectFirst("#menu > a")
                     assertNotNull(firstLinkInMenu)
                     assertEquals("Login", firstLinkInMenu.text())
@@ -37,7 +37,7 @@ class ApplicationTest {
                     login()
                     handleRequest(HttpMethod.Get, "/").apply {
                         assertEquals(HttpStatusCode.OK, response.status())
-                        val document = Jsoup.parse(response.content)
+                        val document = Jsoup.parse(response.content!!)
                         val firstLinkInMenu = document.selectFirst("#menu > ul > li:nth-child(1) > a")
                         assertNotNull(firstLinkInMenu)
                         assertEquals("Settings", firstLinkInMenu.text())
@@ -266,7 +266,7 @@ class ApplicationTest {
                     login()
                     val gistUrl = testGist()
                     val csrfToken = handleRequest(HttpMethod.Get, gistUrl.encodedPath + "/delete").run {
-                        val document = Jsoup.parse(response.content)
+                        val document = Jsoup.parse(response.content!!)
                         val csrf =
                             document.selectFirst("body > div.container > form > input[type=\"hidden\"]:nth-child(2)")
                         csrf?.attr("value")!!
@@ -290,7 +290,7 @@ class ApplicationTest {
                     login()
                     val gistUrl = testGist()
                     val csrfToken = handleRequest(HttpMethod.Get, gistUrl.encodedPath + "/delete").run {
-                        val document = Jsoup.parse(response.content)
+                        val document = Jsoup.parse(response.content!!)
                         val csrf =
                             document.selectFirst("body > div.container > form > input[type=\"hidden\"]:nth-child(2)")
                         csrf?.attr("value")!!
@@ -316,7 +316,7 @@ class ApplicationTest {
                     login()
                     val gistUrl = testGist()
                     val csrfToken = handleRequest(HttpMethod.Get, gistUrl.encodedPath + "/delete").run {
-                        val document = Jsoup.parse(response.content)
+                        val document = Jsoup.parse(response.content!!)
                         val csrf =
                             document.selectFirst("body > div.container > form > input[type=\"hidden\"]:nth-child(2)")
                         csrf?.attr("value")!!
diff --git a/shared/build.gradle b/shared/build.gradle
index 6d85f2d6..8848e33b 100644
--- a/shared/build.gradle
+++ b/shared/build.gradle
@@ -15,11 +15,15 @@ java {
 }
 
 compileKotlin {
-    kotlinOptions.jvmTarget = targetJvm
-    kotlinOptions.apiVersion = "1.4"
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.fromTarget(targetJvm)
+        apiVersion = org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_1_9
+    }
 }
 
 compileTestKotlin {
-    kotlinOptions.jvmTarget = targetJvm
-    kotlinOptions.apiVersion = "1.4"
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.fromTarget(targetJvm)
+        apiVersion = org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_1_9
+    }
 }