diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/identifier/AbstractIdentifierFactory.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/identifier/AbstractIdentifierFactory.java
index 097989c9c4a1556fee2002f12d4770a26fbaa05d..67539a22148f232e2ffd615070be23e9d467e5f2 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/identifier/AbstractIdentifierFactory.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/identifier/AbstractIdentifierFactory.java
@@ -59,7 +59,7 @@ public abstract class AbstractIdentifierFactory
 
     // ----
 
-    private static final String ALLOWED_CODE_CHARACTERS = "A-Z0-9_\\-";
+    private static final String ALLOWED_CODE_CHARACTERS = "A-Z0-9_\\-\\.";
 
     private static final Pattern ALLOWED_CODE_REGEXP =
             Pattern.compile("^[" + ALLOWED_CODE_CHARACTERS + "]+$", Pattern.CASE_INSENSITIVE);