Until then, using a 1.8.8 Eaglercraft client to join a 1.21-enabled server is your best bet for a "modern" experience on the web.
Join the Eaglercraft Discord communities to find verified server IPs that support 1.21 connections. eaglercraft 1.21 1
The long-awaited "Crafter" block that uses Redstone. How to Play Eaglercraft Safely Until then, using a 1
Eaglercraft 1.21.1: Can You Play the Latest Minecraft Update in Your Browser? eaglercraft 1.21 1
Historically, Eaglercraft versions have lagged behind the official Mojang releases because porting thousands of lines of Java code to a browser-compatible format is a massive technical undertaking. The Reality of Eaglercraft 1.21.1