Rated 4 out of 5 stars
First of all congratulations for this amazing add-on, and specially to keep it updated.
I installed the add-on a month ago, and as a result made Thunderbird really slow, specially to scroll up and down the message list. Apparently this has been fixed in a recent version, so it doesn't slow down while scrolling through messages anymore, that's great, thanks!.
The problem that I have now is Thunderbird takes easily 15 seconds to boot and it's a problem with your add-on, since the problem goes ways after disabling it.
Did you face with this slow down problem?
In case it helps, my contact list has 1100 contacts in it and I'm using a private VPS with Nextcloud.
yes I know this problem at startup... for info in your case, at startup CardBook will open 1100 files in the cache, that's why it is slow... I should use a database or grouping the files opening per second... for middle of next year...