Great update.
Great Job by Sony. I never expect Android Oreo on a 2016 phone. But Sony is really caring their customers.
Just updated with the help of this tutorial: https://droidfeats.com/update-xperia-x-compact-variant-android-8-0-oreo-official-firmware/

Xperia X Compact_F5321_34.4.A.0.364_Russia_Generic 8.0.0
Sony Xperia X Compact (F5321) Android 8.0.0 firmware - Generic Russia