One file, and the server says whether players need it too

Keystone is one mod. The same file goes on the server and into a player's client — no server edition, no client edition, no two version numbers to drift apart. The server picks whether it requires the client: a public server lets everybody in, and whoever has the mod also gets the maps, the screens and real colour in chat; a modpack server can require it, because there everybody has it anyway. Two people on one server, one with the mod and one without, are both served correctly — and the second is told what the file would add rather than handed a worse imitation of it.

Added

2 September 2026