Lenovo has just unveiled that it will upgrade seven of its smartphones to Android 5.0 Lollipop which includes the Vibe Z2 Pro, Vibe X2, and the newly announced S90 and P70.

Below are the smartphones that will receive the Android 5.0 Lollipop upgrade:
According to Lenovo, the upgrade will arrive via Over-The-Air (OTA) in the second quarter of 2015.
The company also noted that the upgrade only applies to the models “bought from retail market; operators customized or contract models are not covered.”
source: Lenovo
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Upgraded mine to 5.0.2 last 05/01/15. Some Lenovo apps like anti-virus were missing, some features are integrated in system setting, cylindrical transition animation missing.
Details are indicated in the URL below:
https://forums.lenovo.com/t5/K-S-and-Vibe-Series/The-ROW-Z2-Pro-K920-just-got-the-Lollipop-upgrade/td-p/2073142