Warning: Downgrading Smartphones already on Android Q or LineageOS 17.x to Pie or other OS can cause instability or at worst brick some devices
This hint dates back to the days when the Galaxy S9+ ‘star2lte’ was still running /e/ OS 'O’reo 8.1. With /e/ OS ‘Q’, these restrictions have now ended.[Yesterday I was able to install (3) different customROM’s on the Galaxy S9+ ‘star2lte’ with TWRP 3.5.0_9-0: first [/e/OS ‘Q’ e-0.13-q-20210120, then LineageOS 17.1 for microG and finally /e/ OS ‘Q’ GSI ROM. So far I’ve not been able to register any problems.
This message so far refers to LineageOS 17.1. Where did you read which message?