diff --git a/CHANGES.rst b/CHANGES.rst
index cc2f4676ff8d..f4b63a512b8c 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -3,7 +3,8 @@ Changes in synapse v0.28.0-rc1 (2018-04-24)
 
 Minor performance improvement to federation sending and bug fixes.
 
-(Note: This release does not include state resolutions discussed in matrix live)
+(Note: This release does not include the delta state resolution implementation discussed in matrix live)
+
 
 Features:
 
diff --git a/synapse/storage/schema/delta/48/group_invite_unique.sql b/synapse/storage/schema/delta/48/group_invite_unique.sql
new file mode 100644
index 000000000000..6e3f09411647
--- /dev/null
+++ b/synapse/storage/schema/delta/48/group_invite_unique.sql
@@ -0,0 +1,2 @@
+DROP INDEX groups_invites_g_idx;
+CREATE UNIQUE INDEX groups_invites_g_idx ON group_invites(group_id, user_id);