You are welcome.
Yes, webpack-dev-server went into maintenance mode, so webpack-serve is its official successor.
There is no real difference from user perspective except for the browser limitation as webpack-serve uses websockets to push updates and requires a browser which supports them. The configuration is a bit easier however, there is even real possibility to avoid it at all. Also, integration with CopyWebpackPlugin went smoothly, without any problems which happened in earlier versions. My overall impression is very positive.
From what I read about both packages, the difference is mostly architectural. Over years webpack-dev-server accumulated some hacks to support older browsers and it was pain to maintain them all. So they came with webpack-serve which is faster, smoother, leaner alternative and utilizes modern approaches.
A bit too much writing probably but hopefully somewhat helpful. 