diff --git a/abbot/project.xml b/abbot/project.xml
index 40182937..b6e9c56b 100644
--- a/abbot/project.xml
+++ b/abbot/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-abbot-plugin</id>
diff --git a/announcement/project.xml b/announcement/project.xml
index a43cb3d3..b1ca3fc6 100644
--- a/announcement/project.xml
+++ b/announcement/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-announcement-plugin</id>
diff --git a/ant/project.xml b/ant/project.xml
index f2c4934c..14b1d864 100644
--- a/ant/project.xml
+++ b/ant/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-ant-plugin</id>
diff --git a/antlr/project.xml b/antlr/project.xml
index 79f2a9a2..1894312c 100644
--- a/antlr/project.xml
+++ b/antlr/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-antlr-plugin</id>
diff --git a/aspectj/project.xml b/aspectj/project.xml
index bafcb761..0cad1414 100644
--- a/aspectj/project.xml
+++ b/aspectj/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-aspectj-plugin</id>
diff --git a/castor/project.xml b/castor/project.xml
index e0c8993a..d05626c4 100644
--- a/castor/project.xml
+++ b/castor/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-castor-plugin</id>
diff --git a/changelog/project.xml b/changelog/project.xml
index ed891c40..1532facf 100644
--- a/changelog/project.xml
+++ b/changelog/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-changelog-plugin</id>
diff --git a/changes/project.xml b/changes/project.xml
index 374abcc0..d6a770c5 100644
--- a/changes/project.xml
+++ b/changes/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-changes-plugin</id>
diff --git a/checkstyle/project.xml b/checkstyle/project.xml
index 3626ce6f..d832ccf0 100644
--- a/checkstyle/project.xml
+++ b/checkstyle/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-checkstyle-plugin</id>
diff --git a/clean/project.xml b/clean/project.xml
index d2b853c6..a856cfc8 100644
--- a/clean/project.xml
+++ b/clean/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-clean-plugin</id>
diff --git a/clover/project.xml b/clover/project.xml
index aa6d0b35..223cb398 100644
--- a/clover/project.xml
+++ b/clover/project.xml
@@ -17,7 +17,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-clover-plugin</id>
diff --git a/console/project.xml b/console/project.xml
index 3d0ff43c..3f921b05 100644
--- a/console/project.xml
+++ b/console/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-console-plugin</id>
diff --git a/cruisecontrol/project.xml b/cruisecontrol/project.xml
index 7c8ca233..10941472 100644
--- a/cruisecontrol/project.xml
+++ b/cruisecontrol/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-cruisecontrol-plugin</id>
diff --git a/dashboard/project.xml b/dashboard/project.xml
index aa52cb64..c1fd2755 100644
--- a/dashboard/project.xml
+++ b/dashboard/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-dashboard-plugin</id>
diff --git a/developer-activity/project.xml b/developer-activity/project.xml
index e28fa167..1e9f04ff 100644
--- a/developer-activity/project.xml
+++ b/developer-activity/project.xml
@@ -17,7 +17,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-developer-activity-plugin</id>
diff --git a/dist/project.xml b/dist/project.xml
index f09999cf..6ecc26f3 100644
--- a/dist/project.xml
+++ b/dist/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-dist-plugin</id>
diff --git a/ear/project.xml b/ear/project.xml
index 5539e542..65dd19b2 100644
--- a/ear/project.xml
+++ b/ear/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-ear-plugin</id>
diff --git a/ejb/project.xml b/ejb/project.xml
index fbd8783e..1617b404 100644
--- a/ejb/project.xml
+++ b/ejb/project.xml
@@ -17,7 +17,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-ejb-plugin</id>
diff --git a/examples/project.xml b/examples/project.xml
index afc6f057..1850500a 100644
--- a/examples/project.xml
+++ b/examples/project.xml
@@ -18,7 +18,8 @@
  -->
 
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <!-- the version of maven's project object model -->
 
   <pomVersion>3</pomVersion>
diff --git a/faq/project.xml b/faq/project.xml
index c65bbc1f..2f765f32 100644
--- a/faq/project.xml
+++ b/faq/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-faq-plugin</id>
diff --git a/file-activity/project.xml b/file-activity/project.xml
index a14d85e5..8b59c4fe 100644
--- a/file-activity/project.xml
+++ b/file-activity/project.xml
@@ -17,7 +17,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-file-activity-plugin</id>
diff --git a/genapp/project.xml b/genapp/project.xml
index 037a480d..23b4c073 100644
--- a/genapp/project.xml
+++ b/genapp/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-genapp-plugin</id>
diff --git a/gump/project.xml b/gump/project.xml
index 809196af..170b13c5 100644
--- a/gump/project.xml
+++ b/gump/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-gump-plugin</id>
diff --git a/hibernate/project.xml b/hibernate/project.xml
index bdf08fe6..dc326d8b 100644
--- a/hibernate/project.xml
+++ b/hibernate/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-hibernate-plugin</id>
diff --git a/html2xdoc/project.xml b/html2xdoc/project.xml
index d12e58d8..33bfd854 100644
--- a/html2xdoc/project.xml
+++ b/html2xdoc/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-html2xdoc-plugin</id>
diff --git a/idea/project.xml b/idea/project.xml
index 0280938f..1c6aaa2f 100644
--- a/idea/project.xml
+++ b/idea/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-idea-plugin</id>
diff --git a/j2ee/project.xml b/j2ee/project.xml
index 776ae4e3..14cdf307 100644
--- a/j2ee/project.xml
+++ b/j2ee/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-j2ee-plugin</id>
diff --git a/jalopy/project.xml b/jalopy/project.xml
index 28524759..eef02902 100644
--- a/jalopy/project.xml
+++ b/jalopy/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jalopy-plugin</id>
diff --git a/jar/project.xml b/jar/project.xml
index 714bf7bb..41a26c9c 100644
--- a/jar/project.xml
+++ b/jar/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jar-plugin</id>
diff --git a/java/project.xml b/java/project.xml
index ef97b18b..a0b1672f 100644
--- a/java/project.xml
+++ b/java/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-java-plugin</id>
diff --git a/javacc/project.xml b/javacc/project.xml
index cd31ad7b..48aae214 100644
--- a/javacc/project.xml
+++ b/javacc/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-javacc-plugin</id>
diff --git a/javadoc/project.xml b/javadoc/project.xml
index b3c22e2b..fa5e40ce 100644
--- a/javadoc/project.xml
+++ b/javadoc/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
   -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <artifactId>maven-javadoc-plugin</artifactId>
diff --git a/jboss/project.xml b/jboss/project.xml
index 6503b3e2..a92a59cf 100644
--- a/jboss/project.xml
+++ b/jboss/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jboss-plugin</id>
diff --git a/jbuilder/project.xml b/jbuilder/project.xml
index 3a05760a..6415e704 100644
--- a/jbuilder/project.xml
+++ b/jbuilder/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jbuilder-plugin</id>
diff --git a/jcoverage/project.xml b/jcoverage/project.xml
index 24d2bbf9..25057d0d 100644
--- a/jcoverage/project.xml
+++ b/jcoverage/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jcoverage-plugin</id>
diff --git a/jdepend/project.xml b/jdepend/project.xml
index 47a96cd1..146151bb 100644
--- a/jdepend/project.xml
+++ b/jdepend/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jdepend-plugin</id>
diff --git a/jdiff/project.xml b/jdiff/project.xml
index fbdc478d..411ba5ce 100644
--- a/jdiff/project.xml
+++ b/jdiff/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jdiff-plugin</id>
diff --git a/jellydoc/project.xml b/jellydoc/project.xml
index 993e7e07..5176d76f 100644
--- a/jellydoc/project.xml
+++ b/jellydoc/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jellydoc-plugin</id>
diff --git a/jetty/project.xml b/jetty/project.xml
index 93833c08..b1fcfb1d 100644
--- a/jetty/project.xml
+++ b/jetty/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jetty-plugin</id>
diff --git a/jnlp/project.xml b/jnlp/project.xml
index e31b32e8..fceefcd8 100644
--- a/jnlp/project.xml
+++ b/jnlp/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jnlp-plugin</id>
diff --git a/junit-report/project.xml b/junit-report/project.xml
index 27194145..f6d48640 100644
--- a/junit-report/project.xml
+++ b/junit-report/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-junit-report-plugin</id>
diff --git a/jxr/project.xml b/jxr/project.xml
index b462da8b..0d2d7109 100644
--- a/jxr/project.xml
+++ b/jxr/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-jxr-plugin</id>
diff --git a/license/project.xml b/license/project.xml
index 26f7ae0c..bfaea77f 100644
--- a/license/project.xml
+++ b/license/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-license-plugin</id>
diff --git a/linkcheck/project.xml b/linkcheck/project.xml
index 1015ffc4..c47530b3 100644
--- a/linkcheck/project.xml
+++ b/linkcheck/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-linkcheck-plugin</id>
diff --git a/multichanges/project.xml b/multichanges/project.xml
index 7695d9a6..5a1a1a28 100644
--- a/multichanges/project.xml
+++ b/multichanges/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-multichanges-plugin</id>
diff --git a/multiproject/project.xml b/multiproject/project.xml
index bdbbcc00..f955b2e2 100644
--- a/multiproject/project.xml
+++ b/multiproject/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-multiproject-plugin</id>
diff --git a/native/project.xml b/native/project.xml
index 8bd0daa0..8c084acb 100644
--- a/native/project.xml
+++ b/native/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-native-plugin</id>
diff --git a/nsis/project.xml b/nsis/project.xml
index 79258a8b..fc176f7e 100644
--- a/nsis/project.xml
+++ b/nsis/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <name>Maven NSIS Plug-in</name>
diff --git a/pdf/project.xml b/pdf/project.xml
index 1d3185cf..8588f3d3 100644
--- a/pdf/project.xml
+++ b/pdf/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>${basedir}/../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <artifactId>maven-pdf-plugin</artifactId>
diff --git a/plugin-parent/project.xml b/plugin-parent/project.xml
index c08adbf7..6c8fd128 100644
--- a/plugin-parent/project.xml
+++ b/plugin-parent/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
 
   <pomVersion>3</pomVersion>
   <id>plugin-parent</id>
diff --git a/plugin/project.xml b/plugin/project.xml
index b33bd351..617394d9 100644
--- a/plugin/project.xml
+++ b/plugin/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-plugin-plugin</id>
diff --git a/pmd/project.xml b/pmd/project.xml
index 0ae65b8e..411cac0b 100644
--- a/pmd/project.xml
+++ b/pmd/project.xml
@@ -17,7 +17,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-pmd-plugin</id>
diff --git a/pom/project.xml b/pom/project.xml
index 3a6fd094..1abe2c72 100644
--- a/pom/project.xml
+++ b/pom/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project xmlns="http://maven.apache.org/POM/3.0.0">
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-pom-plugin</id>
diff --git a/rar/project.xml b/rar/project.xml
index 42935e7b..8e8d9928 100644
--- a/rar/project.xml
+++ b/rar/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-rar-plugin</id>
diff --git a/repository/project.xml b/repository/project.xml
index b6f46a75..04c85ea7 100644
--- a/repository/project.xml
+++ b/repository/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-repository-plugin</id>
diff --git a/scm/project.xml b/scm/project.xml
index 6822d103..d4f1727e 100644
--- a/scm/project.xml
+++ b/scm/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-scm-plugin</id>
diff --git a/simian/project.xml b/simian/project.xml
index 956577f3..8c041feb 100644
--- a/simian/project.xml
+++ b/simian/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-simian-plugin</id>
diff --git a/site/project.xml b/site/project.xml
index 47902892..51d4bde7 100644
--- a/site/project.xml
+++ b/site/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-site-plugin</id>
diff --git a/tasklist/project.xml b/tasklist/project.xml
index 550c3b43..105ef2d9 100644
--- a/tasklist/project.xml
+++ b/tasklist/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-tasklist-plugin</id>
diff --git a/test/project.xml b/test/project.xml
index c8b7471a..4caa5364 100644
--- a/test/project.xml
+++ b/test/project.xml
@@ -16,7 +16,8 @@
  * limitations under the License.
  */
  -->
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-test-plugin</id>
diff --git a/touchstone-partner/project.xml b/touchstone-partner/project.xml
index 26a84c0b..86c07805 100644
--- a/touchstone-partner/project.xml
+++ b/touchstone-partner/project.xml
@@ -18,7 +18,8 @@
  -->
 
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-touchstone-partner-plugin</id>
diff --git a/touchstone/project.xml b/touchstone/project.xml
index a1d9c903..3a7af3e8 100644
--- a/touchstone/project.xml
+++ b/touchstone/project.xml
@@ -18,7 +18,8 @@
  -->
 
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-touchstone-plugin</id>
diff --git a/uberjar/project.xml b/uberjar/project.xml
index bffeffe4..c0699ade 100644
--- a/uberjar/project.xml
+++ b/uberjar/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <!-- the version of maven's project object model -->
 
diff --git a/war/project.xml b/war/project.xml
index b2f4edc3..b8cd35f1 100644
--- a/war/project.xml
+++ b/war/project.xml
@@ -18,7 +18,8 @@
  */
  -->
 
-<project>
+<project xmlns="http://maven.apache.org/POM/3.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/3.0.0 http://maven.apache.org/maven-v3_0_0.xsd">
   <extend>../plugin-parent/project.xml</extend>
   <pomVersion>3</pomVersion>
   <id>maven-war-plugin</id>