This query is a bit tricky because it could refer to two different things: a search for the to the popular browser-based Minecraft clone, or a request for a technical guide on how to host/play it. However, since Eaglercraft is currently based on older versions of Minecraft (like 1.8.8 and 1.5.2), there isn't an official "1.21" version of Eaglercraft yet.
: A recent multiplayer teaser was shared on Reddit (April 2026), showcasing functional multiplayer capabilities for version 1.21.11. eaglercraft 1.21