Only downgrade down to the version before the newest one.
Don’t go way back into the archives to version 1.1.
Before you downgrade, I’d highly recommend making sure you have a backup of your site just in case things don’t go as planned and everything gets screwed up.An FTP client allows you to access all of the files on your site. In your FTP client, locate your Word Press files (wp-admin, wp-content, etc.). You can leave all of the other files alone because you will overwrite them in the next step.I use Fire FTP from Firefox and File Zilla is another very popular option. In Fire FTP, they will be the first thing you see when you open your site’s folder. While you’re still in your FTP client, go into the folder where you have the Word Press version you want to downgrade to.The first thing you’re going to need is a previous Word Press release.You can download any of the previous Word Press versions here – Word Press releases.