diff --git a/.gitignore b/.gitignore
index 2f71a88..f53d7ed 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ build
 interfaces
 layers
 *.swp
+*.charm
diff --git a/src/lib/charm/openstack/ovn_chassis.py b/src/lib/charm/openstack/ovn_chassis.py
index cae6bbf..acbab87 100644
--- a/src/lib/charm/openstack/ovn_chassis.py
+++ b/src/lib/charm/openstack/ovn_chassis.py
@@ -20,37 +20,16 @@ import charms.ovn_charm
 charm.use_defaults('charm.default-select-release')
 
 
-class TrainOVNChassisCharm(charms.ovn_charm.DeferredEventMixin,
-                           charms.ovn_charm.BaseTrainOVNChassisCharm):
+class OVNChassisCharm(charms.ovn_charm.DeferredEventMixin,
+                      charms.ovn_charm.BaseOVNChassisCharm):
     # OpenvSwitch and OVN is distributed as part of the Ubuntu Cloud Archive
-    # Pockets get their name from OpenStack releases
-    release = 'train'
-    name = 'ovn-chassis'
-
-    # Setting an empty source_config_key activates special handling of release
-    # selection suitable for subordinate charms
-    source_config_key = ''
-
-
-class UssuriOVNChassisCharm(charms.ovn_charm.DeferredEventMixin,
-                            charms.ovn_charm.BaseUssuriOVNChassisCharm):
-    # OpenvSwitch and OVN is distributed as part of the Ubuntu Cloud Archive
-    # Pockets get their name from OpenStack releases
+    # Pockets get their name from OpenStack releases.
+    #
+    # This defines the earliest version this charm can support, actually
+    # installed version is selected by the principle charm.
     release = 'ussuri'
     name = 'ovn-chassis'
 
     # Setting an empty source_config_key activates special handling of release
     # selection suitable for subordinate charms
     source_config_key = ''
-
-
-class WallabyOVNChassisCharm(charms.ovn_charm.DeferredEventMixin,
-                             charms.ovn_charm.BaseWallabyOVNChassisCharm):
-    # OpenvSwitch and OVN is distributed as part of the Ubuntu Cloud Archive
-    # Pockets get their name from OpenStack releases
-    release = 'wallaby'
-    name = 'ovn-chassis'
-
-    # Setting an empty source_config_key activates special handling of release
-    # selection suitable for subordinate charms
-    source_config_key = ''