The display actually said WDBT-HD? I haven't heard anything about them upgrading. The company that owns them doesn't seem to have any translators under their name, either. There are two in Dothan listing WARB as the parent, though, so maybe one of them might be spun off at some point. One of them is on 107.7 and has been the subject of complaints by WFXX in Georgiana claiming interference, so it's future is uncertain.
There's no logical reason for a news/talk station to broadcast in HD, so I'm wondering if you might've caught WWL's HD via tropo. Happens here from time to time.