I'm actually running the iPad (2017) version but there was no category for that. Anyways, since the recent minecraft pe update (version 1.1.3) I've been getting constant lag, the chunks aren't loading but when they do, it takes 30 seconds - 2 minutes. Lowering the chunk rate does not do anything, nor does lowering any other options. Resetting the app and restarting my device does nothing either, very frustrating. It's very unplayable.