App Versioning is a new feature introduced in Joget v3.  

It lets you manage the version of the application that you are developing, and lets you easily switch between and publish different versions even while in production.  

It is a helpful tool for developers as it allows them to continue working/improving on an application while maintaining a production copy.

Users can, for instance, continue to use version 1 of a published application while developers work on an unpublished version 2.

Update App Version

• Copies processes, forms, datalists, userviews and properties of the current version to the new version
• Does NOT affect any existing running process instances

Update Process Version

• Updates only the process design under the current App version
• Updates existing running instances of the processes found under the current App version to the new design

Further reading: Update Existing Running Process Instances to the Newer Process Flow After Process Changes