download/install thru wi-fi took 30 minutes. wi-fi, 4g, texting, email, music, photos, etc all ok.
many notifications turned on, do not disturb was turned off. sync schedule for imap email needed to be reset.
check other settings that may have been changed.
hope ths helps
Overall it took about 15-20 mins over my internet (wifi) connection to download. It installed fine, first try. I had no issues with the install. I had to fix a few things with notifications on a couple apps that go reset because of MM notifications and how they are handled now. I had to modify a few of my scripts in Tasker due to again modifications in MM notification handling, but I was aware of those prior to the download. Battery usage been about the same or a maybe a little better, not sure I work from home so I am not very far from an outlet, so I don't notice any difference.
So far I have had no issues. I do have a couple of apps that may need to be updated to work better on MM, but other than that running smooth and fast. No problems.
during the process there was a message that after the install/reboot, the back-up pin would be required even though i'm using fingerprint.
what i'm finding is when i shut the phone down to charge, i need to re-enter the pin instead of being able to use the fingerprint.