Google have not released it yet... https://source.android.com/security/bulletin/
(edited) Just received it on my TA-1043. Size 460.4MB Version 8.1 V2.22A
Had already Oreo 8.1.0. Looks like it’s not only a security update, also a system update. First impression; phone responding more quickly.
Nokia, is there a more detailed changelog for the v2.22a update?
Installed this update to TA-1050 and now I am getting random power off / reboots of the phone a few times each day.