The older Zenfone series with the Zenfone 4, Zenfone 5 and Zenfone 6 was to be updated to Android 5.0 Lollipop first in April, then Mid-may and now, according to Asus "as soon as possible." Asus hasn't provided a concrete timeline on the update.
Asus says they are working on the Lollipop update for the Zenfone series and have found some issues which are delaying the rollout. The PadFone S and PadFone Infinity 2 were also in line to get the Lollipop update within this time-frame but they again missed the timeline. Asus further added that the update plan for the Infinity 2 had to be postponed (read canceled) "due to limitation of the processor", because Snapdragon 800 with 2 GB RAM just can't make the cut.
Asus is currently also focusing on the Zenfone 2 series which has received good reviews worldwide. You can have a look at our unboxing and gaming reviews of the Zenfone 2 ZE551ML (2GB RAM) variant.
We will keep you apprised of any changes on this front, stay tuned for updates.
Source: Asus Forums
