I will start by executing the first set of search operations. search results show several relevant GitHub repositories. The first result, "TheCookeringYT/Eaglercraft1.21", seems promising. The second result, "TheiffYT/EaglerCraft-1.21", might be related. The search for "eaglercraft 1.21.1 download" didn't show obvious specific results. The search for "eaglercraft how to play online" shows general instructions. The search for "eaglercraft latest version 2026" shows some recent activity. The search for "Eaglercraft 1.21 1" shows general pages.

A: The most stable and widely used client versions remain 1.8.8 and 1.12.2. A full client based on version 1.21 is not yet complete or stable for public use.