Singleplayer lags on iOS make the game unplayable

Single-player, local Survival world.  After installing 1.6.0, the game has become unplayable due to performance.  Navigation is painfully slow.  Unable to open doors (success rate approximately 1 in 20 clicks).  Performance was generally fluid in previous verion 1.5.3.  I seriously regret installing this version and had to give up after only a few minutes of gameplay.