src/Connector.js

@@ -351,13 +351,29 @@ module.exports = function (Y/* :any */) {
                 }
               })
               */
-              defer.resolve()
+              defer.resolve(m.os && m.os.length > 0)
             })
           } else if (message.type === 'sync done') {
             var self = this
-            this.connections[sender].syncStep2.then(function () {
+            this.connections[sender].syncStep2.then(function (resync) {
+              if (resync) {
+                const answer = {
+                  type: 'sync check',
+                }
+                for (const uid in self.connections) {
+                  if (uid !== sender) {
+                    self.send(uid, answer)
+                  }
+                }
+              }
               self._setSyncedWith(sender)
             })
+          } else if (message.type === 'sync check') {
+            const conn = this.connections[sender]
+            if (conn != null && conn.isSynced) {
+              conn.isSynced = false
+            }
+            this.findNextSyncTarget()
           } else if (message.type === 'update' && canWrite(auth)) {
             if (this.forwardToSyncingClients) {
               for (var client of this.syncingClients) {