Preinstalled incompatible signatures: microG & Pdf Viewer Plus (GSnathan)

[kolAflash]

Another P.S.
If you like to keep/reinstall the Magisk microG installer after an system update, you need to keep TWRP and reflash Magisk via TWRP. To achieve this you need to run TWRP A/B Retention Script (twrp-keep) (from Magisk) before rebooting when you just accepted the update installation. See also:

Preserve TWRP and/or Magisk after system update

Unfortunately the official TWRP app also doesn’t seem work for A/B devices (yet). But there’s a Magisk module: TWRP A/B Retention Script (twrp-keep) I’ll give it a try at the next eOS update.