Can you open source the code base so that I or someone else can maintain it for you? Or at least assist in maintaining?
I'd love to be able to delete by subject too.
I second MattRiddell.
Could you please put the MailHub plugin source code on @github if you have abandoned the project? That would be greatly appreciated.
I just received a message from Anthony, the developer, who assures me that MailHub for Catalina will be out within a month and a Beta version before that.