Lollipop Update is not showed ... topic

Hi,
I have a Nexus 7 ME370T (Wi-Fi Model). I'm currently on 4.4.4 but if I check for updates the message is "System is Updated". No 5.0/5.0.1/5.0.2. OS is original and was never rooted. How can I get OTA updates (don't want to flash from factory images).

Thanks in advance
Stefano