Virtual Collections can now be extended
diff --git a/pom.xml b/pom.xml
index e127b7b..f7b05f3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -9,7 +9,7 @@
 
   <groupId>KorAP-modules</groupId>
   <artifactId>KorAP-lucene-index</artifactId>
-  <version>0.20</version>
+  <version>0.21</version>
   <packaging>jar</packaging>
 
   <name>KorAP-lucene-index</name>