Minecraft Downdating?

I have a question
Are you able to get older versions of minecraft so Mods that won't work with newer versions work again?

you could copy your .minecraft folder and store the copy somewhere safe before you update. then to downgrade just delete the 1.6 .minecraft and replace with your 1.5 backup.

there have been old version posts around...look for them!

Which version do you want to downgrade to?