In my old version of K9 (5.600) unread e-mails used to be highlighted in grey or white.
Also in the overall folder view all unread e-mails across all folders used to be displayed with numbers of the unread e-mails.
Can I setup the new version of K9 to function like the previous one ?
By default the text is bold for unread messages. In the following screenshot the 4th and 5th message on the list have been read, the others are unread.
There is a setting to change the background color for read messages which looks like this:
You can see unread message count on the folders list
Screenshots from 5.726 but I believe this is all the same right up to the current version (5.740)