Ios problems

Hi Neuwe,
Thanks for using the Apple Support Communities. If the screen on your iPhone does not dim/deactivate when you hold it up on a call, leading to inadvertent presses, you may first want to make sure that nothing is obscuring the receiver proximity sensor (remove any cases, screen protectors, etc). If you continue to have this issue, based on what you are describing and the fact that it started after an OS update, you may want to try reinstalling a fresh copy of iOS to help resolve (or at least rule out) any system software issues. Once iOS is reinstalled, you will want to test and see if the issue persists or returns. The process is outlined in the following article under the section "If your device turns on but gets stuck during start up" (the article itself is aimed at a slightly different issue, but the steps outlined are still applicable in this case):

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

Note: While this process generally shouldn't affect your data or settings, it's always best to have a full backup of your data just in case. If you haven't recently backed up your device, you may also find this article helpful:

How to back up your iPhone, iPad, and iPod touch - Apple Support

Regards.