[AC Question]

I just reset my Note 4 before the Marshmallow update. However, when I tried to check for software updates it say I am up to date despite running Lollipop 5.1.1. Any idea on how I can update manually. Phone is stock.

[nahoku]

Are you absolutely certain you want to move to MM???????

The OS has changed quite a few things. Simple things you used to be able to do are now a pain in the you know where.

1) You can't simply eject an external usb device from the notification shade pull down. You now have to go to Settings > Storage to find the eject command.
2) You'll lose all the tabs in Application Manager... no more Downloaded, SD card, Running, All, or Disabled. You will now have to deal with a LONG list of everything on the phone... so scroll your heart out!
3) You now have to enable and enter Developer Options just to see what's running
4) Folder icons look terrible... round and cluttered
5) No more once or default choice option
6) Permission capability... while it might be good for some, is a pain for others.

Note that this is MM on a Verizon Note 4. I don't know if ATT will be the same.

I dislike LP because some functionality was removed from KK, but I hate MM altogether!

Read all you can about what ATT has done before jumping on MM... because it won't be easy (if at all possible) to revert your phone back to LP.

That said, you might want to see if Smart switch or Kies can help you update your phone via your computer. You might also want to go into recovery and wipe/delete the cache partition and then check for updates again. Good luck!