: The most stable and widely available versions on the official Eaglercraft site are 1.5.2 and 1.8.8.
The primary hurdle is the underlying technology. Eaglercraft uses TeaVM to compile Java into JavaScript. While older versions of Minecraft run on Java 8, version 1.16 and above transition toward newer Java versions (like Java 16/17), which are harder to port using current Eaglercraft tools.
