Don't get too excited if you see an update notification on your T-Mobile HTC One or Galaxy Note II today – they're both getting minor updates. Both devices stay on Android 4.1.2, but cheer up. There are phones that don't get any update love.
The HTC One update has version number 1.27.531.8, and is coming via OTA. You may notice this isn't even the 1.29 HTC software revision containing fixes for the camera and sluggish buttons. In fact, T-Mobile says all this update does is improve the performance of Visual Voicemail. This one is an 18MB download, and you have to be completely stock to get it.
The Galaxy Note II is getting a slightly more substantial update, but it's not setting the world on fire either. Update version T889UVBMD1 includes security fixes and Smart Switch. In the likely event you're not familiar with Smart Switch, it's a tool for transferring content between Samsung devices. The Note II update is coming via Samsung Kies and an OTA, so take your pick. The update is 15MB in size, and you (of course) have to be stock to receive it.