diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/Serializer.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/Serializer.kt.mustache
index 31b83578e7e..b1e03a46798 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/Serializer.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/Serializer.kt.mustache
@@ -27,8 +27,8 @@ import com.fasterxml.jackson.databind.SerializationFeature
 import com.fasterxml.jackson.annotation.JsonInclude
 import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 {{/jackson}}
-import java.util.Date
 {{#kotlinx_serialization}}
+import java.util.Date
 import java.math.BigDecimal
 import java.math.BigInteger
 {{^threetenbp}}
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index b80e0390de2..d32b9d22c61 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -6,7 +6,6 @@ import java.time.LocalDate
 import java.time.LocalDateTime
 import java.time.OffsetDateTime
 import java.util.UUID
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index ec931412660..ece5c413e12 100644
--- a/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -4,7 +4,6 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.SerializationFeature
 import com.fasterxml.jackson.annotation.JsonInclude
 import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index b80e0390de2..d32b9d22c61 100644
--- a/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -6,7 +6,6 @@ import java.time.LocalDate
 import java.time.LocalDateTime
 import java.time.OffsetDateTime
 import java.util.UUID
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index ebd1a2a526b..4b9802b3874 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -1,7 +1,6 @@
 package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index acc0b33ae20..fb425461435 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 internal object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
index e77581231c3..e22592e47d7 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
@@ -2,7 +2,6 @@ package org.openapitools.client.infrastructure
 
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
-import java.util.Date
 
 object Serializer {
     @JvmStatic