Asus has finally rolled out the lollipop update to first generation zenfone series smartphones. Last week there was a misconception regarding the update when Asus has posted that they are delay by 3-4 months for the update, but that was just a rookie mistake. The company has pushed the OTA update for the smartphones, The Android 5.0 Lollipop for the ZenFone 4 (A400CG) comes with version 7.3.3, ZenFone 5 (A500CG / A501CG) with version 220.127.116.11, and ZenFone 6 (A600CG / A601CG) with version 18.104.22.168.
The update seems to be rolled out in phases and it might take quite a bit of time to reach the users, as a solution to that Asus has provided OTA zip files that can be flashed manually and the steps to update are clearly mentioned in their forum/website. The company warned users before updating to backup the SD card data as it no longer supports NTFS format SD card thus some of the pre-installed apps might not function as they are intended to do. The official change log is being mentioned in the official forum/website. do check the steps before flashing the update as might format your data completely.