I think, for the most part, Mono is being rolled into Core. From what I've seen, it looks like large chunks of Mono were moved, migrated or otherwise refactored into Core anyway. My reading of this is that what is now the Core runtime, will be what is .Net everywhere, and that while not mentioned, Mono as a separate runtime, much like .Net framework will not see new releases in favor of a single .Net 5.
Re:.NET 5
by dragonwriter on Monday May 06, 2019 @06:41PM
(#19844682)
They seem to indicate that both Mono and CoreCLR runtimes will be maintained and available with different focal use cases as part of .NET 5.
Moving projects from .Net Framework to .Net 5 should be as easy or hard as it was to go from Framework to Core. In my case, this isn't a problem for the current project that I'm working on, but thankfully Microsoft will support .Net Framework 4.8 in maintenance mode for a very long time.