MCPE on IOS crashes after short while

Hi,
We run into the problem that when running MCPE 1.2.3 on an iPad 2, IOS 9.3.5 and 12 Gb memory free, the program crashes frequently and becomes unplayable.

I tried removing all add-ons and packs, did not work. Tried upgrading IOS to the lastest version for IPAd 2, no success. Then tried re-installing the complete MCPE app. Still no result. Sometimes the app crashes while the game did not even start. Sometimes it's possible to play a game for a short while. The graphics render more slowly then in previous versions. In addition to these attempts I tried to play a game with WiFi turned of, that makes no difference. Gamemode set to peaceful gave no other results.

On my laptop (Windows 10) I have none of these issues.

What can I do to get MCPE working again on the IOS platform?

Thanks in advance for your answers.

Kind regards,

Winfried Tiemessen