Sometimes you might want to go back to the previous version of an article. Joomla has that option for you, by default, it is turned on. 

Open the article in your backend to edit. Once you have created an article and saved it for the first time, only then you will see a version button

Process:

• Click on “Version” from the top menu
  
  
  
  
  
• Select the version you want to restore, then click on “restore” button
• Save changes

You can also compare versions, or delete old versions. The * icon is the current version.