Hi,
The Miui 10 download tab have the stable version:
https://xiaomi.eu/community/threads/miui-10-0-10-1-10-2-10-3-10-4-stable-release.47170/
For the last android 8 stable version im thing is:
xiaomi.eu_multi_MIMix2_V10.3.1.0.ODECNXM_v10-8.0.zip
About the histoy, no idea where you can find it.