I've had the Zenfone 2 for about 4 months now, and it's still on 5.0. ASUS has sent out quite a few system updates in that time period, for bugfixes, feature additions, and performance improvements--but no word yet on if and when we may get 5.1 (or 6.0, for that matter).
I have received a few OS updates since getting this tablet a few weeks ago. The latest was two nights ago. The explanatory text described it as a stagefreight fix. It is still at 5.0. The build is WV-V4.3.0_20150917
I ran the zimperium stagefright detector before and after the update. There was no change. It was fully patched in both cases (all green). I wonder what Asus really changed?
-Jem
I have a TF101 epad Transformer & they were horrible about updating it. it shipped with android 3.0 & there were a few updates but Asus never updated it to 4.0. They just left us in the dust. We should be upgraded to marshmallow though.