[maven-release-plugin] prepare for next development iteration
diff --git a/javaparser-core-generators/pom.xml b/javaparser-core-generators/pom.xml
index 98cb40e..e6ad49f 100644
--- a/javaparser-core-generators/pom.xml
+++ b/javaparser-core-generators/pom.xml
@@ -3,7 +3,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-core-metamodel-generator/pom.xml b/javaparser-core-metamodel-generator/pom.xml
index cfce8d2..d4d07c1 100644
--- a/javaparser-core-metamodel-generator/pom.xml
+++ b/javaparser-core-metamodel-generator/pom.xml
@@ -3,7 +3,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-core-serialization/pom.xml b/javaparser-core-serialization/pom.xml
index 8458735..0e44e27 100644
--- a/javaparser-core-serialization/pom.xml
+++ b/javaparser-core-serialization/pom.xml
@@ -2,7 +2,7 @@
 	<parent>
 		<artifactId>javaparser-parent</artifactId>
 		<groupId>com.github.javaparser</groupId>
-		<version>3.6.20</version>
+		<version>3.6.21-SNAPSHOT</version>
 	</parent>
 	<modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-core-testing/pom.xml b/javaparser-core-testing/pom.xml
index e5c6de7..67e8bfd 100644
--- a/javaparser-core-testing/pom.xml
+++ b/javaparser-core-testing/pom.xml
@@ -2,7 +2,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-core/pom.xml b/javaparser-core/pom.xml
index 5cf6416..5f79193 100644
--- a/javaparser-core/pom.xml
+++ b/javaparser-core/pom.xml
@@ -2,7 +2,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-symbol-solver-core/pom.xml b/javaparser-symbol-solver-core/pom.xml
index 6d017b2..7cab799 100644
--- a/javaparser-symbol-solver-core/pom.xml
+++ b/javaparser-symbol-solver-core/pom.xml
@@ -3,7 +3,7 @@
   <parent>
       <artifactId>javaparser-parent</artifactId>
       <groupId>com.github.javaparser</groupId>
-      <version>3.6.20</version>
+      <version>3.6.21-SNAPSHOT</version>
   </parent>    
   <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-symbol-solver-logic/pom.xml b/javaparser-symbol-solver-logic/pom.xml
index c3e85a4..b526f62 100644
--- a/javaparser-symbol-solver-logic/pom.xml
+++ b/javaparser-symbol-solver-logic/pom.xml
@@ -3,7 +3,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-symbol-solver-model/pom.xml b/javaparser-symbol-solver-model/pom.xml
index 21d833b..3b52816 100644
--- a/javaparser-symbol-solver-model/pom.xml
+++ b/javaparser-symbol-solver-model/pom.xml
@@ -3,7 +3,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/javaparser-symbol-solver-testing/pom.xml b/javaparser-symbol-solver-testing/pom.xml
index 7456c11..3380478 100644
--- a/javaparser-symbol-solver-testing/pom.xml
+++ b/javaparser-symbol-solver-testing/pom.xml
@@ -3,7 +3,7 @@
     <parent>
         <artifactId>javaparser-parent</artifactId>
         <groupId>com.github.javaparser</groupId>
-        <version>3.6.20</version>
+        <version>3.6.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/pom.xml b/pom.xml
index a9147cb..5eba866 100644
--- a/pom.xml
+++ b/pom.xml
@@ -15,7 +15,7 @@
     <groupId>com.github.javaparser</groupId>
     <artifactId>javaparser-parent</artifactId>
     <packaging>pom</packaging>
-    <version>3.6.20</version>
+    <version>3.6.21-SNAPSHOT</version>
 
     <name>javaparser-parent</name>
     <url>https://github.com/javaparser</url>
@@ -135,7 +135,7 @@
         <connection>scm:git:git://github.com/javaparser/javaparser.git</connection>
         <developerConnection>scm:git:git@github.com:javaparser/javaparser.git</developerConnection>
         <url>https://github.com/javaparser/javaparser.git</url>
-        <tag>javaparser-parent-3.6.20</tag>
+        <tag>HEAD</tag>
     </scm>
 
     <issueManagement>