The "121" is not an official Mojang version number. Instead, it serves three critical purposes in the unblocked gaming community:
Most "121" builds are based on Minecraft 1.8.8. This is the golden age for PvP (Player vs Player). You get: eaglercraft unblocked 121
represents a fascinating intersection of web technology, community-driven preservation, and the constant battle between restricted networks and digital freedom. A Technical Marvel: Minecraft in a Browser Eaglercraft The "121" is not an official Mojang version number