HOW 2004 RUNESCAPE FIT A MULTIPLAYER RPG INTO 56K DIAL-UP

Summary from the TLDR Dev newsletter

RuneScape successfully ran a massive multiplayer RPG on 56k dial-up by meticulously minimizing the bandwidth required for every player action. This efficiency was achieved using a custom protocol where the client and server shared an identical world model, allowing the system to transmit only minimal changes, sometimes as little as a single bit for stationary players, via techniques like bit-packing.