diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-retrofit2/infrastructure/ApiClient.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-retrofit2/infrastructure/ApiClient.kt.mustache
index ea19748fbfbc..2d64978b0c2a 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-retrofit2/infrastructure/ApiClient.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-retrofit2/infrastructure/ApiClient.kt.mustache
@@ -21,6 +21,7 @@ import {{packageName}}.auth.HttpBearerAuth
 {{/authMethods}}
 {{/hasAuthMethods}}
 
+import okhttp3.Call
 import okhttp3.Interceptor
 import okhttp3.OkHttpClient
 import retrofit2.Retrofit
@@ -56,7 +57,7 @@ import okhttp3.MediaType.Companion.toMediaType
     private var baseUrl: String = defaultBasePath,
     private val okHttpClientBuilder: OkHttpClient.Builder? = null{{^kotlinx_serialization}},
     private val serializerBuilder: {{#gson}}Gson{{/gson}}{{#moshi}}Moshi.{{/moshi}}Builder = Serializer.{{#gson}}gson{{/gson}}{{#moshi}}moshi{{/moshi}}Builder{{/kotlinx_serialization}},
-    private val okHttpClient : OkHttpClient? = null,
+    private val callFactory : Call.Factory? = null,
     private val converterFactory: Converter.Factory? = null,
 ) {
     private val apiAuthorizations = mutableMapOf<String, Interceptor>()
@@ -303,8 +304,8 @@ import okhttp3.MediaType.Companion.toMediaType
     }
 
     fun <S> createService(serviceClass: Class<S>): S {
-        val usedClient = this.okHttpClient ?: clientBuilder.build()
-        return retrofitBuilder.client(usedClient).build().create(serviceClass)
+        val usedCallFactory = this.callFactory ?: clientBuilder.build()
+        return retrofitBuilder.callFactory(usedCallFactory).build().create(serviceClass)
     }
 
     private fun normalizeBaseUrl() {
diff --git a/samples/client/petstore/kotlin-retrofit2-kotlinx_serialization/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-retrofit2-kotlinx_serialization/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index a5aaa332be80..3bb7d9c4d663 100644
--- a/samples/client/petstore/kotlin-retrofit2-kotlinx_serialization/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-retrofit2-kotlinx_serialization/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -7,6 +7,7 @@ import org.openapitools.client.auth.OAuth
 import org.openapitools.client.auth.OAuth.AccessTokenListener
 import org.openapitools.client.auth.OAuthFlow
 
+import okhttp3.Call
 import okhttp3.Interceptor
 import okhttp3.OkHttpClient
 import retrofit2.Retrofit
@@ -21,7 +22,7 @@ import okhttp3.MediaType.Companion.toMediaType
 class ApiClient(
     private var baseUrl: String = defaultBasePath,
     private val okHttpClientBuilder: OkHttpClient.Builder? = null,
-    private val okHttpClient : OkHttpClient? = null,
+    private val callFactory : Call.Factory? = null,
     private val converterFactory: Converter.Factory? = null,
 ) {
     private val apiAuthorizations = mutableMapOf<String, Interceptor>()
@@ -180,8 +181,8 @@ class ApiClient(
     }
 
     fun <S> createService(serviceClass: Class<S>): S {
-        val usedClient = this.okHttpClient ?: clientBuilder.build()
-        return retrofitBuilder.client(usedClient).build().create(serviceClass)
+        val usedCallFactory = this.callFactory ?: clientBuilder.build()
+        return retrofitBuilder.callFactory(usedCallFactory).build().create(serviceClass)
     }
 
     private fun normalizeBaseUrl() {
diff --git a/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index cc63b570177a..51a186e48faa 100644
--- a/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -7,6 +7,7 @@ import org.openapitools.client.auth.OAuth
 import org.openapitools.client.auth.OAuth.AccessTokenListener
 import org.openapitools.client.auth.OAuthFlow
 
+import okhttp3.Call
 import okhttp3.Interceptor
 import okhttp3.OkHttpClient
 import retrofit2.Retrofit
@@ -22,7 +23,7 @@ class ApiClient(
     private var baseUrl: String = defaultBasePath,
     private val okHttpClientBuilder: OkHttpClient.Builder? = null,
     private val serializerBuilder: Moshi.Builder = Serializer.moshiBuilder,
-    private val okHttpClient : OkHttpClient? = null,
+    private val callFactory : Call.Factory? = null,
     private val converterFactory: Converter.Factory? = null,
 ) {
     private val apiAuthorizations = mutableMapOf<String, Interceptor>()
@@ -183,8 +184,8 @@ class ApiClient(
     }
 
     fun <S> createService(serviceClass: Class<S>): S {
-        val usedClient = this.okHttpClient ?: clientBuilder.build()
-        return retrofitBuilder.client(usedClient).build().create(serviceClass)
+        val usedCallFactory = this.callFactory ?: clientBuilder.build()
+        return retrofitBuilder.callFactory(usedCallFactory).build().create(serviceClass)
     }
 
     private fun normalizeBaseUrl() {
diff --git a/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index bee954129e6b..4aa4323fc5b2 100644
--- a/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-retrofit2/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -7,6 +7,7 @@ import org.openapitools.client.auth.OAuth
 import org.openapitools.client.auth.OAuth.AccessTokenListener
 import org.openapitools.client.auth.OAuthFlow
 
+import okhttp3.Call
 import okhttp3.Interceptor
 import okhttp3.OkHttpClient
 import retrofit2.Retrofit
@@ -21,7 +22,7 @@ class ApiClient(
     private var baseUrl: String = defaultBasePath,
     private val okHttpClientBuilder: OkHttpClient.Builder? = null,
     private val serializerBuilder: Moshi.Builder = Serializer.moshiBuilder,
-    private val okHttpClient : OkHttpClient? = null,
+    private val callFactory : Call.Factory? = null,
     private val converterFactory: Converter.Factory? = null,
 ) {
     private val apiAuthorizations = mutableMapOf<String, Interceptor>()
@@ -180,8 +181,8 @@ class ApiClient(
     }
 
     fun <S> createService(serviceClass: Class<S>): S {
-        val usedClient = this.okHttpClient ?: clientBuilder.build()
-        return retrofitBuilder.client(usedClient).build().create(serviceClass)
+        val usedCallFactory = this.callFactory ?: clientBuilder.build()
+        return retrofitBuilder.callFactory(usedCallFactory).build().create(serviceClass)
     }
 
     private fun normalizeBaseUrl() {