Hi, please add a support for beta version of minecraft !
The 1.7.3, the download can be find on internet easily
Thanks.
EDIT:
Official Link of some betas:
Beta 1.8 pre : https://assets.minecraft.net/1_8-pre/minecraft_server.jar
Beta 1.8 pre2 : https://assets.minecraft.net/1_8-pre2/minecraft_server.jar
Beta 1.9 pre : https://assets.minecraft.net/1_9-pre/minecraft_server.jar
Beta 1.9 pre2 : https://assets.minecraft.net/1_9-pre2/minecraft_server.jar
Beta 1.9 pre3 : https://assets.minecraft.net/1_9-pre3/minecraft_server.jar
Beta 1.9 pre4 : https://assets.minecraft.net/1_9-pre4/minecraft_server.jar
Beta 1.9 pre5 : https://assets.minecraft.net/1_9-pre5/minecraft_server.jar
Beta 1.9 pre6 : https://assets.minecraft.net/1_9-pre6/minecraft_server.jar
Older: https://www.youtube.com/watch?v=yN9WeLfdYEg
Or.. Add an "Open Mod" options 