Issues while updating other plugins with Native PHP Sessions active

Dear support team,

there is a message generated upon activation, that unexpected output (2516 chars) was generated during activiation. So far, I could not encounter strange behaviour besides my other topic raised (“Deprecated JS call and critical site-health message”).

However, prior to any update of other plugins, I need to deactivate your Native PHP Sessions plugin in order to avoid heavy warnings and error messages, e.g. that a session was encountered and that jQuery wasn’t compatible with “QUIRK” Mode. The latter seems to result from invalid DOCTYPE statements.
Those warnings appear in the front-end as well!!

Perhaps, you could look into that.

Thanks

Michael