From the PCMag
Yahoo wrote:"In December of 2015, we announced a brand new Yahoo Messenger for mobile, the Web and in Yahoo Mail on the desktop, built on a new modern platform. This complete revamp brings users an incredibly fast, beautiful and smart way to send – and unsend – messages, photos and animated GIFs in 1:1 and group conversations. While today we provide basic interoperation between the legacy product and the new Messenger, we encourage all of our users to complete their transition to the new Yahoo Messenger as we will no longer support the legacy platform as of August 5, 2016. We intend to continue our focused efforts on the new Messenger, with a goal of delivering the best experience to our users,"
Sounds good to me. They're breathing new life into their service at the small expense of an archaic desktop program.
Also from the article:
While you can't currently download the new iteration of Yahoo Messenger to your computer as a standalone Windows or Mac app, Yahoo claims it is working on a version. It hasn't published a timeline for the release in its official Yahoo Messenger FAQ, but you can sign up for updates to the in-progress program.
I'm assuming there won't be any loss of contacts. That would be a juvenile mistake on Yahoo's part.