diff --git a/Dockerfile.synchronizer b/Dockerfile.synchronizer
index c71235a..522a582 100644
--- a/Dockerfile.synchronizer
+++ b/Dockerfile.synchronizer
@@ -16,7 +16,7 @@
 
 # xosproject/hippie-oss-synchronizer
 
-FROM xosproject/xos-synchronizer-base:2.0.0
+FROM xosproject/xos-synchronizer-base:2.1.9
 
 COPY xos/synchronizer /opt/xos/synchronizers/hippie-oss
 COPY VERSION /opt/xos/synchronizers/hippie-oss/
diff --git a/VERSION b/VERSION
index 3018fdc..9084fa2 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.1.0-dev0
+1.1.0
diff --git a/xos/synchronizer/models/hippie-oss.xproto b/xos/synchronizer/models/hippie-oss.xproto
index 5149c0c..07d4aca 100644
--- a/xos/synchronizer/models/hippie-oss.xproto
+++ b/xos/synchronizer/models/hippie-oss.xproto
@@ -16,7 +16,7 @@
     required string serial_number = 2 [max_length = 254, null = False, db_index = False, blank = False, tosca_key=True, unique = True];
     required string authentication_state = 3 [default = "AWAITING", choices = "(('AWAITING', 'Awaiting'), ('STARTED', 'Started'), ('REQUESTED', 'Requested'), ('APPROVED', 'Approved'), ('DENIED', 'Denied'), )", max_length = 50, null = False, db_index = False, blank = False];
     required string of_dpid = 4 [max_length = 254, null = False, db_index = False, blank = False];
-    optional int32 c_tag = 5 [null = True, db_index = False, blank = False, unique = True, feedback_state = True];
+    optional int32 c_tag = 5 [null = True, db_index = False, blank = True, unique = True, feedback_state = True];
 }
 
 message HippieOSSWhiteListEntry (XOSBase) {