diff --git a/lib/shared/threads/protocols/dm-thread-protocol.js b/lib/shared/threads/protocols/dm-thread-protocol.js
--- a/lib/shared/threads/protocols/dm-thread-protocol.js
+++ b/lib/shared/threads/protocols/dm-thread-protocol.js
@@ -922,6 +922,8 @@
     membershipMessageNotifAction: messageNotifyTypes.SET_UNREAD,
 
     shouldConvertIDs: false,
+
+    dataIsBackedUp: true,
   });
 
 function pendingThreadType(numberOfOtherMembers: number) {
diff --git a/lib/shared/threads/protocols/keyserver-thread-protocol.js b/lib/shared/threads/protocols/keyserver-thread-protocol.js
--- a/lib/shared/threads/protocols/keyserver-thread-protocol.js
+++ b/lib/shared/threads/protocols/keyserver-thread-protocol.js
@@ -679,6 +679,8 @@
     membershipMessageNotifAction: messageNotifyTypes.NONE,
 
     shouldConvertIDs: true,
+
+    dataIsBackedUp: true,
   });
 
 function pendingThreadType(numberOfOtherMembers: number) {
diff --git a/lib/shared/threads/thread-spec.js b/lib/shared/threads/thread-spec.js
--- a/lib/shared/threads/thread-spec.js
+++ b/lib/shared/threads/thread-spec.js
@@ -400,6 +400,12 @@
   +threadActivityUpdatedByDMActivityHandler: boolean,
   +membershipMessageNotifAction: MessageNotifyType,
   +shouldConvertIDs: boolean,
+  // This flag specifies that all data created or updated should be included
+  // in backup (compaction and logs), and backup created by the primary
+  // device is considered to be the source of truth for this.
+  // In practice, this means that this data storage is in tables
+  // that are included in the backup.
+  +dataIsBackedUp: boolean,
 };
 
 export type ThreadSpec<