How to update Magisk to 20.4?

[inte]

I have dual boot LineageOS and SailfishOS Gemni PDA.
No issues updating SailfishOS to the recent release.
LineageOS is still 8.1 and I can't find anz newer release. Even worse, I really can't figure out to update Magisk to the recent release, 20.1.
No matter which method I'm choosing, is it twrp or direct install (or even manually installing the zip file), Magisk remains on 19.1 even though the installer returns sucess installing.
Is there any more recent LineageOS (and Magisk) available for the Gemini, and how could it be installed?
Thank you in advance!!

[Raniyah]

As I know, you can simply update the Magisk via Magisk manager app

[tpp]

Can't update Magisk either, on trimmed stock ROM.