My partner did an update this morning, and it's been a disaster.... the IMS Service message has popped up all day long.
After searching on line for various 'cures' modified something, which seems to have worked on a Samsung Galaxy Neo 5. (I removed the mini SD card before hand)
Select MESSAGES
Select MORE
Select CONFIGURATION MESSAGE
Choose a previous version- I chose an August 2015 version
Select INSTALL
Let it download - an 'OK' message to say it has downloaded comes up
So far... no horrible pop-ups... and happiness is restored!