I have had the tablet for over a year, had a current Verizon sim card in it the whole time, and yet I'm still on 4.4.2. Which works fine, but I want to fix this upgrade problem especially with M coming out soon, I would like to have lollipop on my Nexus. I've tried wiping Google services framework a couple times as well, but still my tablet says your system is up to date. I would rather not wipe my data. Any help would be appreciated.