Android 16 is now available for Teracube 2e (2020) & Teracube 2e (2021) Android 16.0.1 for Teracube 2e 1st Batch Zirconia (SN: 2020)
Since it seems like some people care, the OTA-only update for Zirconia was:
15.0.2+c235e82.zirconia.user
We have something special cooking internally, cannot wait to share it 
(You wouldn’t guess whats coming to your T2E!)