We already knew that Microsoft would be deprecating the classic Paint app in future versions of Windows 10, but things are becoming more of a reality now. A message in the much-loved Paint.exe app in Windows 10 Build 17063 is now warning of classic Paint being replaced by Paint 3D (via Neowin.)
The notification is not automatic but instead comes up when a user presses on the "Product Alert" icon in the ribbon of the classic Paint App in build 17063 (seen above.) It specifically warns users that "This version of Paint will soon be replaced with Paint 3D. Classic Paint will then become available in the Store."
It was already known that Paint would be coming to the Microsoft Store, so this is not exactly earth-shattering news. It does, though, hint that Microsoft may or may not be eventually removing Classic Paint and releasing the Microsoft Store app in time for the Redstone 4 release this Spring. More will likely develop in the months ahead, so best to keep Paint.exe close to your heart in the meantime before it's gone for good.