Thank you very much for your effort. Arrow is the best ROM for me, and I've tried many. The most fluid, unhindered in transitions, stable ... Congratulations and thanks again.A new official build will release soon!
You can view all the changelogs here, I think I won't write changelogs in easy manner here since It seems it's time waste, no one seems to care anyways.
Rom changelogs: https://arrowos.net/changelog.php
Device changelogs: https://github.com/ArrowOS-Devices/android_device_xiaomi_vayu/commits/arrow-12.0
Kernel changelogs: https://github.com/ArrowOS-Devices/android_kernel_xiaomi_vayu/commits/arrow-12.0