diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/build.gradle.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/build.gradle.mustache
index c807ca500964..1e72595d0ab5 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/build.gradle.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/build.gradle.mustache
@@ -2,7 +2,7 @@ group '{{groupId}}'
 version '{{artifactVersion}}'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-gson/build.gradle b/samples/client/petstore/kotlin-gson/build.gradle
index 0c7a11ec147a..95625ca00921 100644
--- a/samples/client/petstore/kotlin-gson/build.gradle
+++ b/samples/client/petstore/kotlin-gson/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-jackson/build.gradle b/samples/client/petstore/kotlin-jackson/build.gradle
index 96578e36308e..9561dac51197 100644
--- a/samples/client/petstore/kotlin-jackson/build.gradle
+++ b/samples/client/petstore/kotlin-jackson/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-json-request-string/build.gradle b/samples/client/petstore/kotlin-json-request-string/build.gradle
index 21ab84c47bbc..e3d4632a52ed 100644
--- a/samples/client/petstore/kotlin-json-request-string/build.gradle
+++ b/samples/client/petstore/kotlin-json-request-string/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/build.gradle b/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/build.gradle
index 0c7a11ec147a..95625ca00921 100644
--- a/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/build.gradle
+++ b/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-moshi-codegen/build.gradle b/samples/client/petstore/kotlin-moshi-codegen/build.gradle
index 191e341d8a01..7d52cdbb5a0f 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/build.gradle
+++ b/samples/client/petstore/kotlin-moshi-codegen/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-nonpublic/build.gradle b/samples/client/petstore/kotlin-nonpublic/build.gradle
index 21ab84c47bbc..e3d4632a52ed 100644
--- a/samples/client/petstore/kotlin-nonpublic/build.gradle
+++ b/samples/client/petstore/kotlin-nonpublic/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-nullable/build.gradle b/samples/client/petstore/kotlin-nullable/build.gradle
index 21ab84c47bbc..e3d4632a52ed 100644
--- a/samples/client/petstore/kotlin-nullable/build.gradle
+++ b/samples/client/petstore/kotlin-nullable/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-okhttp3/build.gradle b/samples/client/petstore/kotlin-okhttp3/build.gradle
index bb1a30055950..b12573a85ccf 100644
--- a/samples/client/petstore/kotlin-okhttp3/build.gradle
+++ b/samples/client/petstore/kotlin-okhttp3/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-retrofit2-rx3/build.gradle b/samples/client/petstore/kotlin-retrofit2-rx3/build.gradle
index b870989c9853..f0281c383a22 100644
--- a/samples/client/petstore/kotlin-retrofit2-rx3/build.gradle
+++ b/samples/client/petstore/kotlin-retrofit2-rx3/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-retrofit2/build.gradle b/samples/client/petstore/kotlin-retrofit2/build.gradle
index a41b15463635..0a6481e6d153 100644
--- a/samples/client/petstore/kotlin-retrofit2/build.gradle
+++ b/samples/client/petstore/kotlin-retrofit2/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-string/build.gradle b/samples/client/petstore/kotlin-string/build.gradle
index 21ab84c47bbc..e3d4632a52ed 100644
--- a/samples/client/petstore/kotlin-string/build.gradle
+++ b/samples/client/petstore/kotlin-string/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin-threetenbp/build.gradle b/samples/client/petstore/kotlin-threetenbp/build.gradle
index 0123235eeeb9..49fdda22715a 100644
--- a/samples/client/petstore/kotlin-threetenbp/build.gradle
+++ b/samples/client/petstore/kotlin-threetenbp/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }
 
diff --git a/samples/client/petstore/kotlin/build.gradle b/samples/client/petstore/kotlin/build.gradle
index 21ab84c47bbc..e3d4632a52ed 100644
--- a/samples/client/petstore/kotlin/build.gradle
+++ b/samples/client/petstore/kotlin/build.gradle
@@ -2,7 +2,7 @@ group 'org.openapitools'
 version '1.0.0'
 
 wrapper {
-    gradleVersion = '4.9'
+    gradleVersion = '6.8.1'
     distributionUrl = "https://services.gradle.org/distributions/gradle-$gradleVersion-all.zip"
 }