diff --git a/src/main/org/apache/tools/ant/taskdefs/defaults.properties b/src/main/org/apache/tools/ant/taskdefs/defaults.properties
index 4adf5085d..a3d262cc2 100644
--- a/src/main/org/apache/tools/ant/taskdefs/defaults.properties
+++ b/src/main/org/apache/tools/ant/taskdefs/defaults.properties
@@ -29,6 +29,8 @@ fixcrlf=org.apache.tools.ant.taskdefs.FixCRLF
 
 # optional tasks
 script=org.apache.tools.ant.taskdefs.optional.Script
+netrexxc=org.apache.tools.ant.taskdefs.optional.NetRexxC
+renameext=org.apache.tools.ant.taskdefs.optional.RenameExtensions
 
 # deprecated ant tasks (kept for back compatibility)
 javadoc2=org.apache.tools.ant.taskdefs.Javadoc