al_version (AppletLoader version) is a number used in versions prior to Java Edition Alpha to uniquely identify a client version of the game.
al_version is a positive floating-point number given as a parameter to the LWJGL AppletLoader in the HTML code of
It is used to specify a unique version for each jar file to cache them for re-use.
If the stored al_version matches the latest jar file, that jar file is re-used; otherwise a new jar is downloaded.
Indev and Infdev
|Java Edition Classic|
|?||Added al_version in order to run Minecraft as an applet on Minecraft.net.|
|Java Edition Indev|
|?||Reset al_version back to 1.0.|
|Java Edition Alpha|
|v1.0.1||Removed al_version as the game now uses the launcher and not AppletLoader.|
- Minecraft.net/play.jsp (source) – Wayback Machine, May 25, 2009. "<param name="al_version" value="5.17">".
- AppletLoader documentation – Legacy LWJGL Javadocs