diff --git a/apps/pom.xml b/apps/pom.xml
index 69f903e71..c11a7da2e 100644
--- a/apps/pom.xml
+++ b/apps/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-parent</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
     <artifactId>struts2-apps</artifactId>
     <packaging>pom</packaging>
diff --git a/apps/rest-showcase/pom.xml b/apps/rest-showcase/pom.xml
index 660759cec..a0f50bfe7 100644
--- a/apps/rest-showcase/pom.xml
+++ b/apps/rest-showcase/pom.xml
@@ -24,12 +24,12 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-apps</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-rest-showcase</artifactId>
     <packaging>war</packaging>
-    <version>2.5.20</version>
+    <version>2.5.21-SNAPSHOT</version>
     <name>Struts 2 Rest Showcase Webapp</name>
     <description>Struts 2 Rest Showcase Example</description>
 
diff --git a/apps/showcase/pom.xml b/apps/showcase/pom.xml
index 73e737deb..24059c9fe 100644
--- a/apps/showcase/pom.xml
+++ b/apps/showcase/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-apps</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-showcase</artifactId>
diff --git a/assembly/pom.xml b/assembly/pom.xml
index 6d1126144..90a4abef3 100644
--- a/assembly/pom.xml
+++ b/assembly/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-parent</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-assembly</artifactId>
diff --git a/bom/pom.xml b/bom/pom.xml
index 4efe807d7..af8f03e6a 100644
--- a/bom/pom.xml
+++ b/bom/pom.xml
@@ -30,7 +30,7 @@
     </parent>
 
     <artifactId>struts2-bom</artifactId>
-    <version>2.5.20</version>
+    <version>2.5.21-SNAPSHOT</version>
     <packaging>pom</packaging>
 
     <name>Struts 2 Bill of Materials</name>
@@ -45,7 +45,7 @@
     </licenses>
 
     <properties>
-        <struts-version.version>2.5.20</struts-version.version>
+        <struts-version.version>2.5.21-SNAPSHOT</struts-version.version>
         <maven.site.skip>true</maven.site.skip>
         <maven.site.deploy.skip>true</maven.site.deploy.skip>
     </properties>
@@ -181,6 +181,6 @@
     </dependencyManagement>
 
   <scm>
-    <tag>STRUTS_2_5_20</tag>
+    <tag>STRUTS_2_5_16</tag>
   </scm>
 </project>
diff --git a/bundles/admin/pom.xml b/bundles/admin/pom.xml
index 10d48f19d..30ae372bb 100644
--- a/bundles/admin/pom.xml
+++ b/bundles/admin/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-osgi-bundles</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-osgi-admin-bundle</artifactId>
diff --git a/bundles/demo/pom.xml b/bundles/demo/pom.xml
index 6b1831683..fb0d86108 100644
--- a/bundles/demo/pom.xml
+++ b/bundles/demo/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-osgi-bundles</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-osgi-demo-bundle</artifactId>
diff --git a/bundles/pom.xml b/bundles/pom.xml
index a036f5e1a..8f14b6f5f 100755
--- a/bundles/pom.xml
+++ b/bundles/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-parent</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-osgi-bundles</artifactId>
diff --git a/core/pom.xml b/core/pom.xml
index fab7c60ee..f20c4e6f0 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-parent</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
     <artifactId>struts2-core</artifactId>
     <packaging>jar</packaging>
diff --git a/plugins/bean-validation/pom.xml b/plugins/bean-validation/pom.xml
index f03661172..9d382cc57 100644
--- a/plugins/bean-validation/pom.xml
+++ b/plugins/bean-validation/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
diff --git a/plugins/cdi/pom.xml b/plugins/cdi/pom.xml
index 4b8e933cd..9cb3ff8f3 100644
--- a/plugins/cdi/pom.xml
+++ b/plugins/cdi/pom.xml
@@ -25,7 +25,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-cdi-plugin</artifactId>
diff --git a/plugins/config-browser/pom.xml b/plugins/config-browser/pom.xml
index 79416e3c3..103e71bc3 100644
--- a/plugins/config-browser/pom.xml
+++ b/plugins/config-browser/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-config-browser-plugin</artifactId>
diff --git a/plugins/convention/pom.xml b/plugins/convention/pom.xml
index ff0794d71..0944fe050 100644
--- a/plugins/convention/pom.xml
+++ b/plugins/convention/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-convention-plugin</artifactId>
diff --git a/plugins/dwr/pom.xml b/plugins/dwr/pom.xml
index d50be0e8f..e4c65b4bd 100644
--- a/plugins/dwr/pom.xml
+++ b/plugins/dwr/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-dwr-plugin</artifactId>
diff --git a/plugins/embeddedjsp/pom.xml b/plugins/embeddedjsp/pom.xml
index 316f19a51..144648112 100644
--- a/plugins/embeddedjsp/pom.xml
+++ b/plugins/embeddedjsp/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-embeddedjsp-plugin</artifactId>
diff --git a/plugins/gxp/pom.xml b/plugins/gxp/pom.xml
index bab556bfa..ca8a993aa 100644
--- a/plugins/gxp/pom.xml
+++ b/plugins/gxp/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-gxp-plugin</artifactId>
diff --git a/plugins/jasperreports/pom.xml b/plugins/jasperreports/pom.xml
index 15d8cd476..510d14498 100644
--- a/plugins/jasperreports/pom.xml
+++ b/plugins/jasperreports/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-jasperreports-plugin</artifactId>
diff --git a/plugins/javatemplates/pom.xml b/plugins/javatemplates/pom.xml
index b65f406ac..71587667e 100644
--- a/plugins/javatemplates/pom.xml
+++ b/plugins/javatemplates/pom.xml
@@ -25,7 +25,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-javatemplates-plugin</artifactId>
diff --git a/plugins/jfreechart/pom.xml b/plugins/jfreechart/pom.xml
index d57fec33f..df6224dee 100644
--- a/plugins/jfreechart/pom.xml
+++ b/plugins/jfreechart/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
    </parent>
 
     <artifactId>struts2-jfreechart-plugin</artifactId>
diff --git a/plugins/json/pom.xml b/plugins/json/pom.xml
index 8e932e95f..99eff641e 100644
--- a/plugins/json/pom.xml
+++ b/plugins/json/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-json-plugin</artifactId>
diff --git a/plugins/junit/pom.xml b/plugins/junit/pom.xml
index 80dda5c19..a860bfec9 100644
--- a/plugins/junit/pom.xml
+++ b/plugins/junit/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-junit-plugin</artifactId>
diff --git a/plugins/osgi/pom.xml b/plugins/osgi/pom.xml
index 4601a3965..b0f1e04b4 100644
--- a/plugins/osgi/pom.xml
+++ b/plugins/osgi/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-osgi-plugin</artifactId>
diff --git a/plugins/oval/pom.xml b/plugins/oval/pom.xml
index 130d61239..0e0755e5e 100644
--- a/plugins/oval/pom.xml
+++ b/plugins/oval/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-oval-plugin</artifactId>
diff --git a/plugins/pell-multipart/pom.xml b/plugins/pell-multipart/pom.xml
index 7cfad6354..856e3f687 100644
--- a/plugins/pell-multipart/pom.xml
+++ b/plugins/pell-multipart/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-pell-multipart-plugin</artifactId>
diff --git a/plugins/plexus/pom.xml b/plugins/plexus/pom.xml
index 0ff5cff99..c7e4dc582 100644
--- a/plugins/plexus/pom.xml
+++ b/plugins/plexus/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-plexus-plugin</artifactId>
diff --git a/plugins/pom.xml b/plugins/pom.xml
index 9f70df740..a2d65a4d4 100644
--- a/plugins/pom.xml
+++ b/plugins/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-parent</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-plugins</artifactId>
diff --git a/plugins/portlet-tiles/pom.xml b/plugins/portlet-tiles/pom.xml
index 1fcef98bd..cf6e8e73d 100644
--- a/plugins/portlet-tiles/pom.xml
+++ b/plugins/portlet-tiles/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-portlet-tiles-plugin</artifactId>
diff --git a/plugins/portlet/pom.xml b/plugins/portlet/pom.xml
index 657c3bce2..64577e4fc 100644
--- a/plugins/portlet/pom.xml
+++ b/plugins/portlet/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-portlet-plugin</artifactId>
diff --git a/plugins/rest/pom.xml b/plugins/rest/pom.xml
index 06711181d..df626dc41 100644
--- a/plugins/rest/pom.xml
+++ b/plugins/rest/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-rest-plugin</artifactId>
diff --git a/plugins/sitegraph/pom.xml b/plugins/sitegraph/pom.xml
index ce1bbc30f..ad3649e65 100644
--- a/plugins/sitegraph/pom.xml
+++ b/plugins/sitegraph/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-sitegraph-plugin</artifactId>
diff --git a/plugins/sitemesh/pom.xml b/plugins/sitemesh/pom.xml
index bf67ca79f..7754852fb 100644
--- a/plugins/sitemesh/pom.xml
+++ b/plugins/sitemesh/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-sitemesh-plugin</artifactId>
diff --git a/plugins/spring/pom.xml b/plugins/spring/pom.xml
index 59547eeed..777670123 100644
--- a/plugins/spring/pom.xml
+++ b/plugins/spring/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-spring-plugin</artifactId>
diff --git a/plugins/testng/pom.xml b/plugins/testng/pom.xml
index 40dfe026b..ad5b591f8 100644
--- a/plugins/testng/pom.xml
+++ b/plugins/testng/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-testng-plugin</artifactId>
diff --git a/plugins/tiles/pom.xml b/plugins/tiles/pom.xml
index 10dbc5fc2..917090168 100644
--- a/plugins/tiles/pom.xml
+++ b/plugins/tiles/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.struts</groupId>
         <artifactId>struts2-plugins</artifactId>
-        <version>2.5.20</version>
+        <version>2.5.21-SNAPSHOT</version>
     </parent>
 
     <artifactId>struts2-tiles-plugin</artifactId>
diff --git a/pom.xml b/pom.xml
index 8fe57422d..b341a10a1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -29,7 +29,7 @@
 
     <modelVersion>4.0.0</modelVersion>
     <artifactId>struts2-parent</artifactId>
-    <version>2.5.20</version>
+    <version>2.5.21-SNAPSHOT</version>
     <packaging>pom</packaging>
     <name>Struts 2</name>
     <url>http://struts.apache.org/</url>
@@ -51,7 +51,7 @@
         <connection>scm:git:https://gitbox.apache.org/repos/asf/struts.git</connection>
         <developerConnection>scm:git:https://gitbox.apache.org/repos/asf/struts.git</developerConnection>
         <url>https://github.com/apache/struts/</url>
-        <tag>STRUTS_2_5_20</tag>
+        <tag>STRUTS_2_5_19</tag>
     </scm>
 
     <issueManagement>