Revert from 4b3 back to 3.6

One year ago I update the dude from the 3.6 version to the 4 beta 3. Since them I have constantly crashes. I read about some memory leak in the 4 beta 3 version, and after one year waiting for an beta 4 version that could fix my problem, I decided do rever to 3.6.

Dows any one here knows how to revert back the configuration from 4 beta 3 to 3.6?