diff --git a/wire-ios-sync-engine/Source/Public/WireSyncEngine.h b/wire-ios-sync-engine/Source/Public/WireSyncEngine.h
index 19accd3f293..6724811802b 100644
--- a/wire-ios-sync-engine/Source/Public/WireSyncEngine.h
+++ b/wire-ios-sync-engine/Source/Public/WireSyncEngine.h
@@ -22,7 +22,6 @@
 // PRIVATE
 #import <WireSyncEngine/ZMBlacklistVerificator.h>
 #import <WireSyncEngine/ZMAuthenticationStatus.h>
-#import <WireSyncEngine/ZMAPSMessageDecoder.h>
 #import <WireSyncEngine/NSError+ZMUserSessionInternal.h>
 #import <WireSyncEngine/ZMOperationLoop.h>
 #import <WireSyncEngine/ZMOperationLoop+Private.h>
diff --git a/wire-ios-sync-engine/Source/Synchronization/Strategies/UserClientRequestStrategy.swift b/wire-ios-sync-engine/Source/Synchronization/Strategies/UserClientRequestStrategy.swift
index cba96ea3696..e6432917e45 100644
--- a/wire-ios-sync-engine/Source/Synchronization/Strategies/UserClientRequestStrategy.swift
+++ b/wire-ios-sync-engine/Source/Synchronization/Strategies/UserClientRequestStrategy.swift
@@ -259,6 +259,7 @@ public final class UserClientRequestStrategy: ZMObjectSyncStrategy, ZMObjectStra
 
         if keys.contains(ZMUserClientNeedsToUpdateSignalingKeysKey) {
             do {
+                // what are these: signaling keys? what is it for?
                 return try requestsFactory.updateClientSignalingKeysRequest(
                     userClient,
                     apiVersion: apiVersion