Ipad mini 6

Hi, I was using an ipadmini4 which i calibrated way back when purchased. Recently i upgraded to the latest model 6.

I have discovered that calibrating ipads is no longer possble. As i have been working exclusively with images created on ipad. I was emailing images to professional printers for large format printing for years without colour issues. Now, due to upgrading i am facing the prospect of having to stop all work and exhibitions. I require some certainty and consistancy to continue. Does ANYONE know a way to achieve something close to a calibrated result? I mostly use pixelmator and artistpro apps.