Web supports custom email categories, keywords, flags or labels (depending how you call them). Is there means to have these properties displayed in an email client? DoveCot support custom labels. Are these used by Webtop or is it a proprietary solution, so that they cannot only be displayed from the web ui?
I confirm that both the tags and the flags are written in the email file.
The tags are certainly compatible with Thunderbird and perhaps with other clients that I have never tested, while the flags should be compatible with Outlook (I have not tried personally).
do you (or someone else) know an Android IMAP-Client which can display these flags?
unfortunately I don’t know … the flags are typical of Outlook, I don’t know if the Outlook client for Android has this support … never tried and maybe I’ll never try it