I'm playing on homecoming, what is this about i24, i25 server etc... thing? What's homecoming on?
Basically, CoX released its patches as "issues", as they'd usually be adding content that would advance the story of the world and it's supposed to be a comic book thing. Issue 23 was the last patch the game was on when it was shut down, issue 24 was the source code that was being developed internally for release and was nearly ready for deployment; that's what was leaked to Leandro by a dev when the shutdown happened, and issue 25 is Leandro's own fork of that source he's built over 8 years on his own private server.
i25 contains numerous balance and content changes that make the game way, way easier than it was intended to be. A determined player can level to 50 and max out their incarnate slots in a few days. You don't even need to do incarnate content to get incarnate materials. You can switch factions by talking to an NPC rather than doing tip missions. I think they removed most types of merits. The cost of merit awards was brought way down for everything. Combined with terrible balance decisions, it's completely trivialized most of the content in the game, which wasn't that hard to begin with.
i24 is the game pretty much in the state it was at when it was shut down, just with the stuff the devs were adding for a new patch.
Homecoming is running i25 and driving its development. Changes to the i25 code get made there since Leandro is a part of that server, and other servers running i25 don't have access to the source so they can really only make trivial changes to what's being run. Rebirth is the first i24 server, and with the i24 source being public, server operators will be able to patch it however they want. I really, really don't like the Homecoming devs - the changes they make are completely arbitrary, done in secret, and then forced on the community without feedback. This morning when I joined rebirth there was a GM discussing in the help channel with players what they were going to do about a few things, and how they were going to hold votes to determine what the community wanted for the outcome. The only downside right now is that Rebirth only has around 80 people logged in.