StyleCop would be a helpful example here. The current version appears (or at least seems to be) dead and/or dying [1]. It has been cloned to github [2] (from codeplex) but nobody is making an effort. I would be willing _but_ after further research I found out that in fact it is sort of rising as a re-implementation with all the Microsoft open sourcing [3]. Which is really great...except the effort of finding this out wasn't exactly easy for me and I was pretty interested in finding out what was going on.
It seems like this is sort of the middle ground of one still being valuable and the replacement not being fully ready but at some point you would hope there would be an announcement on the original project's page (or something). As just a consumer/user I can point people I know or projects I manage at this information but what about people who just think "StyleCop is dead" when they see there hasn't really been activity for weeks/months/years/etc? Not as a member of either project it would be nice to communicate findings like this outwardly, do you reach out to the owners of the projects and see if they will do something? Do you just post to the discussions on the old and point to the new? As just the end-user of some of this how do you get other people informed?
[1] http://stylecop.codeplex.com/ [2] https://github.com/citizenmatt/StyleCop [3] https://github.com/DotNetAnalyzers/StyleCopAnalyzers