Winamp has finally published a new version after many years of ... delays.
The new version is 5.9.0 Build 9999 (x86). You can download it at www.Winamp.com.
I've tested the new version on Windows 10 and it seems to work perfectly. I did need to reinstall Altacast (for streaming) after the new install of Winamp, and that seems perfect as well.
Even after all these years, Winamp is still my favorite media player for most audio and streaming (to Caster.fm), and I highly recommend it.
EDIT: The way I understand it is that they are now working on a major upgrade/overhaul of Winamp, and I'm looking forward to that as well.
Please let me know if you have any questions or need help of any kind.
Happy streaming!