Of course, if you update, you need to update EVERYTHING. Not just software, or firmware. IOS must be kept up to date as well.. Some software updates are to adjust to new IOS updates.
Again, "disconnects" and app stopping are 2 completely different things. The RC flys the aircraft, the app just gives you a visual and some additional controls.
There is NO REASON for a mishap if the app drops out. UNLESS you are flying outside of the line of sight and do not understand how to use the distance on the RC to guide it back home.
No one can explain why thousands of people have no issues with firmware using a specific phone or tablet, but there is a couple percent of users with exact same equipment that are convinced their mavic wont work with current firmware. See the problem with that?
Switch device to airplane mode, shut down all other running apps, messaging, and shut facebook and instagram type apps OFF. If you havent done a hard reboot on your phone or tablet in awhile, that is also a GREAT idea before you fly.