reverting back to 1.09

[Sjafi]

Are you able to revert back to 1.09 without having to lose 1.10? Meaning, I can play both without having to revert every single time. Is there a way to do this? Say, I have a 1.09 icon and a 1.10 beta icon on my desktop. I remember hearing abotu this, but I have forgotten how to do it.

If anyone knows how, I'd appreciate if you let me in on it :)

-Sjafi