Wow just wow, this update really has ruined my iphone 6s. I backed up the phone through iTunes and downgraded it, all went well. Then I decided to update it 10.3 via iTunes and once it had done that I tried to restore my earlier backup, only to realise it wont do it because the backup was done on 10.3 so wont let me restore that backup on 10.2.1. Anyhow no big deal I thought, my phone is backed up on icloud as it is. So restored my stuff from the icloud and again its hanging on my phone, message, whatsapp..pretty much every app that I have backed up through icloud is hanging and will not work at all.
So it pretty much means I have lost everything on my phone ie I cant restore any data from icloud because for some odd reason this update has screwed everything up. Ive never EVER known a phone update to go this badly :/.
Not sure what else I can do now, the phone is basically useless...im so fed up I just feel like smashing the crap out of it lol.