Unless I’m misunderstanding your question, the specific server is more important than the software they’re running; it doesn’t matter if the software is being developed long-term if the server shuts down in the short-term… your community will go down with it.

Your community will not go down with a software dying or a server dying. As long as the server does not die surprisingly, you can just move to a new server, announcing on the old server that you have moved. Active members will follow then.