It uses protocol version 14 and requires at least Java SE 5. The "AlphaVer" ARG and Modified Versions
Since this version is not officially listed in the standard Minecraft Launcher "Historical" list, you need to add it manually or use a third-party launcher. Use a Custom Launcher: Tools like Prism Launcher make this easiest. Enable Historical Versions:
Enable .
: Go to the "Settings" tab and check the box that says "Show historical versions of Minecraft: Java Edition in the Launcher."