Thank you for your fast reply.
D) Description of installation
I dragged and dropped the unpacked installation folder to the terminal. The installation folder was placed in the /home/downloads folder. Then I ran ‘sudo install.sh’ instead of ‘sudo ./install.sh’.
E) Used version
Which version of anki was involved i can’t say certainly. I had once installed version 2.1.15 as normal and flathub package. I thought i used the linux package from the website for more than a half year. The version I used had the old UI. I also found a version 2.1.35 folder direct in my /home folder.
After looking into the version history on github I think update notifications should have appeared more often, if I used the package from the website. I can not remember to have installed an update this year.