Email messages will be marked as "read" even though I dont want this

hello to the forum and to the k9-developers

i am using k9-mail for years and i do not want that a email will be marked as “read” on my server when i use my k9-client on my rooted android10 (custom-rom) xiaomi.
always in thunderbird the emails will be marked as “read” even though i made the setting in my k9-mail (do not mark as read on the server when opening the email…)
…but in thunderbird on ubuntu linux all emails marked as “read”

because on my home pc in my thunderbird main-office-email-client i do not see “unread” emails and so I often forget about important things.

as i installed from f-droid i got info that it will work for older versions…

merry christmas from germany to a big global planet
and thank you for an important and very necessary solution for me

Are you using pop3 or IMAP?

hello Gunter_Konigsmann

I only use two accounts with IMAP on my Android (one is gmail and hetzner/germany)

On gmail I had once the problem that nails changed between read and unread in Thunderbird without obvious cause.
For me the solution was to right-click on the inbox and to tell Thunderbird to rebuild the index.

For me gmail+k9+Thunderbird works fine. But that wouldn’t be the first time that google behaves differently for different users…

thank you, I just tried to make a new index and we will see…
but is this really a longlasting solution or is this a todo all the time?
or might this be a thunderbird problem to post in another forum?
yes! and about googles strange behavior:
i cannot stand changings all the time anymore which causing time-intensive and anoying modifications in other cooperating apps or whatever so i decided to leave contacts and calendar and account to finally escape tracking attacks. without all these its a lot quiter on my computers
only gmail is still used as a second mail-account