diff --git a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJson.kt b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJson.kt
index 0773557e3..dfddd3879 100644
--- a/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJson.kt
+++ b/core/data/src/commonMain/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJson.kt
@@ -11,7 +11,10 @@ internal data class ProfileCardJson(
     val occupation: String,
     val link: String,
     val image: String,
-    @Deprecated("Use cardType instead", replaceWith = ReplaceWith("cardType"))
+    @Deprecated(
+        "Let's use cardType, but keep it for compatibility.",
+        replaceWith = ReplaceWith("cardType")
+    )
     val theme: String? = null,
     @SerialName("card_type")
     val cardType: String? = null,
@@ -22,7 +25,7 @@ internal fun ProfileCardJson.toModel() = ProfileCard.Exists(
     occupation = occupation,
     link = link,
     image = image,
-    cardType = checkNotNull(cardType ?: theme).toProfileCardType(),
+    cardType = checkNotNull(cardType ?: cardType).toProfileCardType(),
 )
 
 internal fun String.toProfileCardType() = ProfileCardType.valueOf(this)
diff --git a/core/data/src/commonTest/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJsonTest.kt b/core/data/src/commonTest/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJsonTest.kt
index acde3bee6..b83a0c924 100644
--- a/core/data/src/commonTest/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJsonTest.kt
+++ b/core/data/src/commonTest/kotlin/io/github/droidkaigi/confsched/data/profilecard/ProfileCardJsonTest.kt
@@ -24,7 +24,7 @@ class ProfileCardJsonTest {
         assertEquals("test occupation", profileCardJson.occupation)
         assertEquals("https://github.com/DroidKaigi/conference-app-2024", profileCardJson.link)
         assertEquals("BASE64_ENCODED_SAMPLE_IMAGE_STRING", profileCardJson.image)
-        assertEquals("Iguana", profileCardJson.theme)
+        assertEquals("Iguana", profileCardJson.cardType)
         assertNull(profileCardJson.cardType)
     }
 
@@ -44,7 +44,7 @@ class ProfileCardJsonTest {
         assertEquals("test occupation", profileCardJson.occupation)
         assertEquals("https://github.com/DroidKaigi/conference-app-2024", profileCardJson.link)
         assertEquals("BASE64_ENCODED_SAMPLE_IMAGE_STRING", profileCardJson.image)
-        assertNull(profileCardJson.theme)
+        assertNull(profileCardJson.cardType)
         assertEquals("Iguana", profileCardJson.cardType)
     }