Is it worth to deprecate Rack::RELEASE already? It would be nice to keep both around for a while to give time for applications to drop older rack versions so they don't also have to case-when around this in addition to everything else. It's a single line so the maintenance burden here is pretty much non-existant.

I'm okay with considering different options (e.g. do nothing, or not deprecating it), however it will be between 6-12 months before this is actually released, and then there will be at least another 6-12 months for another release which actually removes it. I don't think that's unreasonable.

Yeah, I know it will probably be a while still until this is actually released. The thought that my compatibility code I wrote explicitly to avoid deprecations starts throwing deprecations doesn't sound like the most pleasant experience to me.

Since this is so simple, I'd prefer for this to stay around deprecation-less for a while yet, until Rack 4 (or something else far in the future where libraries can reasonably be assumed to no longer support Rack < 3.2) so people don't have to worry about defined?(Rack::VERSION) ? Rack::VERSION : Rack::RELEASE in addition to the other things.

I know there's Rack.release which doesn't change but since a large portion of gems define Foo::VERSION the first think I go for is some kind of constant for this.