Since the old minecraft.net login servers were shutdown because of the OpenSSL bug, a lot of old Minecraft launchers don't work anymore.
I have many instances of Minecraft ranging from Alpha 1.1 to 1.2.5, almost all of them being modded in some way.
What's common between then is that they use the old .minecraft directory structure from pre-1.6.
I'm not sure if there's currently a launcher that can use the current login servers and launch these installs.
Please, I really don't want to convert all of these to the current system, if that's even possible.
Other launchers do still work, like the Technic Launcher, FTB Launcher, AtLauncher. I recommend using multimc, as it uses the old launcher format for the pre1.6 versions.
I've had no problems with using my modded jars with it, but I would recommend making an instance with the right version first, and running it, before replacing the jar with a modded one.
I have many instances of Minecraft ranging from Alpha 1.1 to 1.2.5, almost all of them being modded in some way.
What's common between then is that they use the old .minecraft directory structure from pre-1.6.
I'm not sure if there's currently a launcher that can use the current login servers and launch these installs.
Please, I really don't want to convert all of these to the current system, if that's even possible.
I've had no problems with using my modded jars with it, but I would recommend making an instance with the right version first, and running it, before replacing the jar with a modded one.