No date announced yet, but they did announce that more information will be released during a stream on July 17th. Check out the Crunchyroll article for additional information. Series synopsis for the source manga:
Years ago, Genma promised his old friend Soun Tendo that Ranma would marry one of Soun’s three daughters and carry on the family’s martial arts school. Except that the girl picked to be Ranma’s bride doesn’t seem to like him, Ranma keeps getting into fights…and did we mention that whole changing into a girl thing?
Plenty of time to finish it before watching the remake! What better way to compare/contrast?
Seriously though, I expect it will be a while before this actually comes out. There had been some leaks that this was in the works for a little while. So, what I suspect happened is that they went ahead and announced this now to get ahead of things while continuing to prepare more for their planned announcement stream scheduled for the 17th.