diff --git a/adapter-mode/pom.xml b/adapter-mode/pom.xml
index 4505bb3..045787a 100644
--- a/adapter-mode/pom.xml
+++ b/adapter-mode/pom.xml
@@ -10,6 +10,18 @@
     <modelVersion>4.0.0</modelVersion>
 
     <artifactId>adapter-mode</artifactId>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
 
 </project>
\ No newline at end of file
diff --git a/factory-mode/pom.xml b/factory-mode/pom.xml
index b3d3513..f1bd53d 100644
--- a/factory-mode/pom.xml
+++ b/factory-mode/pom.xml
@@ -14,6 +14,18 @@
     <name>factory-mode</name>
     <!-- FIXME change it to the project's website -->
     <url>http://www.example.com</url>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
     <dependencies>
         <dependency>
diff --git a/javayh-common/pom.xml b/javayh-common/pom.xml
index 5f95ff1..2a44636 100644
--- a/javayh-common/pom.xml
+++ b/javayh-common/pom.xml
@@ -14,4 +14,16 @@
     <name>javayh-common</name>
 
     <url>http://www.javayh.cloud</url>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 </project>
diff --git a/pom.xml b/pom.xml
index 5ddaf37..cb835af 100644
--- a/pom.xml
+++ b/pom.xml
@@ -28,9 +28,9 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-        <java.version>14</java.version>
-        <maven.compiler.source>14</maven.compiler.source>
-        <maven.compiler.target>14</maven.compiler.target>
+        <java.version>8</java.version>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
         <maven.compiler.encoding>UTF-8</maven.compiler.encoding>
         <maven.compiler.compilerArgs>--enable-preview</maven.compiler.compilerArgs>
         <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
diff --git a/proxy-mode/pom.xml b/proxy-mode/pom.xml
index e8a8b32..d51b0e3 100644
--- a/proxy-mode/pom.xml
+++ b/proxy-mode/pom.xml
@@ -10,6 +10,18 @@
     <modelVersion>4.0.0</modelVersion>
 
     <artifactId>proxy-mode</artifactId>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
 
 </project>
\ No newline at end of file
diff --git a/state-mode/pom.xml b/state-mode/pom.xml
index 666895f..56226ba 100644
--- a/state-mode/pom.xml
+++ b/state-mode/pom.xml
@@ -10,6 +10,18 @@
     <modelVersion>4.0.0</modelVersion>
 
     <artifactId>state-mode</artifactId>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
     <dependencies>
         <dependency>
             <groupId>com.javayh</groupId>
diff --git a/strategist-mode/pom.xml b/strategist-mode/pom.xml
index 83ee3cf..c08e2bf 100644
--- a/strategist-mode/pom.xml
+++ b/strategist-mode/pom.xml
@@ -13,6 +13,18 @@
 
     <name>strategist-model</name>
     <url>http://www.javayh.cloud</url>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
 
     <dependencies>
diff --git a/template-mode/pom.xml b/template-mode/pom.xml
index f2654c8..6be42ed 100644
--- a/template-mode/pom.xml
+++ b/template-mode/pom.xml
@@ -14,6 +14,18 @@
     <name>template-mode</name>
     <!-- FIXME change it to the project's website -->
     <url>http://www.example.com</url>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
     <dependencies>
         <dependency>