Ive noticed an issue with Server 4.6.0 and Client iOS 1.5.2.
When I have multiple devices connected to same account. Only the device I use first is receiving new messages. The others remain outdated(without the new messages). The only way to update the chat is by forcing the app to update using refresh gesture(slide down).
I can replicate it in my iPhone and iPad.
The mobile client should always be updated. This can be done by making sure the server is notifying all the connected clients or updating the client everytime it is activated(get focus).