diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache
index e7059406f3d1..f3c3109f4e29 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/buildGradleKts.mustache
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 {{#interfaceOnly}}
diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/pom.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/pom.mustache
index 190b3e46ec9e..76dfa9767896 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/pom.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-boot/pom.mustache
@@ -59,7 +59,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-cloud/pom.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-cloud/pom.mustache
index e8d760b95207..9f70706f7efd 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-cloud/pom.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/libraries/spring-cloud/pom.mustache
@@ -69,7 +69,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-spring-cloud/pom.xml b/samples/server/petstore/kotlin-spring-cloud/pom.xml
index ececa13784d9..a6b6639f7a3a 100644
--- a/samples/server/petstore/kotlin-spring-cloud/pom.xml
+++ b/samples/server/petstore/kotlin-spring-cloud/pom.xml
@@ -52,7 +52,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-spring-default/build.gradle.kts b/samples/server/petstore/kotlin-spring-default/build.gradle.kts
index 87318fc5e130..e956b616df71 100644
--- a/samples/server/petstore/kotlin-spring-default/build.gradle.kts
+++ b/samples/server/petstore/kotlin-spring-default/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-spring-default/pom.xml b/samples/server/petstore/kotlin-spring-default/pom.xml
index c7589ea91c55..ed6a78fd3ffe 100644
--- a/samples/server/petstore/kotlin-spring-default/pom.xml
+++ b/samples/server/petstore/kotlin-spring-default/pom.xml
@@ -43,7 +43,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-bigdecimal-default/build.gradle.kts b/samples/server/petstore/kotlin-springboot-bigdecimal-default/build.gradle.kts
index 87318fc5e130..e956b616df71 100644
--- a/samples/server/petstore/kotlin-springboot-bigdecimal-default/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-bigdecimal-default/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-bigdecimal-default/pom.xml b/samples/server/petstore/kotlin-springboot-bigdecimal-default/pom.xml
index c7589ea91c55..ed6a78fd3ffe 100644
--- a/samples/server/petstore/kotlin-springboot-bigdecimal-default/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-bigdecimal-default/pom.xml
@@ -43,7 +43,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts b/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts
index 87318fc5e130..e956b616df71 100644
--- a/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-delegate/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-delegate/pom.xml b/samples/server/petstore/kotlin-springboot-delegate/pom.xml
index c7589ea91c55..ed6a78fd3ffe 100644
--- a/samples/server/petstore/kotlin-springboot-delegate/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-delegate/pom.xml
@@ -43,7 +43,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts b/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts
index 87318fc5e130..e956b616df71 100644
--- a/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-modelMutable/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-modelMutable/pom.xml b/samples/server/petstore/kotlin-springboot-modelMutable/pom.xml
index c7589ea91c55..ed6a78fd3ffe 100644
--- a/samples/server/petstore/kotlin-springboot-modelMutable/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-modelMutable/pom.xml
@@ -43,7 +43,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-multipart-request-model/build.gradle.kts b/samples/server/petstore/kotlin-springboot-multipart-request-model/build.gradle.kts
index 87318fc5e130..e956b616df71 100644
--- a/samples/server/petstore/kotlin-springboot-multipart-request-model/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-multipart-request-model/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-multipart-request-model/pom.xml b/samples/server/petstore/kotlin-springboot-multipart-request-model/pom.xml
index c7589ea91c55..ed6a78fd3ffe 100644
--- a/samples/server/petstore/kotlin-springboot-multipart-request-model/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-multipart-request-model/pom.xml
@@ -43,7 +43,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-reactive-without-flow/build.gradle.kts b/samples/server/petstore/kotlin-springboot-reactive-without-flow/build.gradle.kts
index 568be3488b17..e2f66299c1f1 100644
--- a/samples/server/petstore/kotlin-springboot-reactive-without-flow/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-reactive-without-flow/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-reactive-without-flow/pom.xml b/samples/server/petstore/kotlin-springboot-reactive-without-flow/pom.xml
index fc671acde310..80ae9216e1e3 100644
--- a/samples/server/petstore/kotlin-springboot-reactive-without-flow/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-reactive-without-flow/pom.xml
@@ -44,7 +44,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts b/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts
index 568be3488b17..e2f66299c1f1 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-reactive/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-reactive/pom.xml b/samples/server/petstore/kotlin-springboot-reactive/pom.xml
index fc671acde310..80ae9216e1e3 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-reactive/pom.xml
@@ -44,7 +44,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-source-swagger1/build.gradle.kts b/samples/server/petstore/kotlin-springboot-source-swagger1/build.gradle.kts
index 6a425af8a353..0e1a003d2859 100644
--- a/samples/server/petstore/kotlin-springboot-source-swagger1/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-source-swagger1/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-source-swagger1/pom.xml b/samples/server/petstore/kotlin-springboot-source-swagger1/pom.xml
index f64e391e05df..31f4899ccbe3 100644
--- a/samples/server/petstore/kotlin-springboot-source-swagger1/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-source-swagger1/pom.xml
@@ -44,7 +44,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-source-swagger2/build.gradle.kts b/samples/server/petstore/kotlin-springboot-source-swagger2/build.gradle.kts
index 02dda8ee6d23..a024c20a2a9c 100644
--- a/samples/server/petstore/kotlin-springboot-source-swagger2/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-source-swagger2/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-source-swagger2/pom.xml b/samples/server/petstore/kotlin-springboot-source-swagger2/pom.xml
index 4e934ad51154..2c1eb5b4ae8a 100644
--- a/samples/server/petstore/kotlin-springboot-source-swagger2/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-source-swagger2/pom.xml
@@ -44,7 +44,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-springfox/build.gradle.kts b/samples/server/petstore/kotlin-springboot-springfox/build.gradle.kts
index 4a927dcde674..a5e654a22c9f 100644
--- a/samples/server/petstore/kotlin-springboot-springfox/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-springfox/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot-springfox/pom.xml b/samples/server/petstore/kotlin-springboot-springfox/pom.xml
index cfdc5e8c6a40..c733bf0da18b 100644
--- a/samples/server/petstore/kotlin-springboot-springfox/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-springfox/pom.xml
@@ -44,7 +44,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot-x-kotlin-implements/build.gradle.kts b/samples/server/petstore/kotlin-springboot-x-kotlin-implements/build.gradle.kts
index d1c663986d73..f0cd582d7879 100644
--- a/samples/server/petstore/kotlin-springboot-x-kotlin-implements/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot-x-kotlin-implements/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 tasks.bootJar {
diff --git a/samples/server/petstore/kotlin-springboot-x-kotlin-implements/pom.xml b/samples/server/petstore/kotlin-springboot-x-kotlin-implements/pom.xml
index 852c00952ba9..54f4f6767beb 100644
--- a/samples/server/petstore/kotlin-springboot-x-kotlin-implements/pom.xml
+++ b/samples/server/petstore/kotlin-springboot-x-kotlin-implements/pom.xml
@@ -42,7 +42,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>
diff --git a/samples/server/petstore/kotlin-springboot/build.gradle.kts b/samples/server/petstore/kotlin-springboot/build.gradle.kts
index 2af5e54061e5..3507e44d515a 100644
--- a/samples/server/petstore/kotlin-springboot/build.gradle.kts
+++ b/samples/server/petstore/kotlin-springboot/build.gradle.kts
@@ -17,7 +17,7 @@ repositories {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.jvmTarget = "1.8"
+    kotlinOptions.jvmTarget = "11"
 }
 
 plugins {
diff --git a/samples/server/petstore/kotlin-springboot/pom.xml b/samples/server/petstore/kotlin-springboot/pom.xml
index dfd0d3a9f6b6..cab717f26a33 100644
--- a/samples/server/petstore/kotlin-springboot/pom.xml
+++ b/samples/server/petstore/kotlin-springboot/pom.xml
@@ -42,7 +42,7 @@
                     <compilerPlugins>
                         <plugin>spring</plugin>
                     </compilerPlugins>
-                    <jvmTarget>1.8</jvmTarget>
+                    <jvmTarget>11</jvmTarget>
                 </configuration>
                 <executions>
                     <execution>