An administrator or user with the appropriate security rights can create a new version of a flow by cloning / copying an existing flow. This allows users to safely change the flow configuration whilst having the option to revert to an older version if required.
To create a new version of an existing flow, locate the flow from Flow Definitions screen and click on the view/edit pencil icon.
Click on the [+] button located on the right side of the screen in the Flow Version section on the Edit Flow Definition page.
A new flow version is created which is an exact copy of the active flow version. If there is no active flow version, a copy of the most recently created version is created. The new version of the flow is inactive when created so that user can make changes to the new version and then activate it after making changes. When the newly created flow version is activated, the old version of the flow is deactivated automatically.
Things to Note
There is no limit to the number of versions you can create for a flow
User Group Screen Permission - View, Edit and Configure rights required:
Flows - Configuration
Flows - Instance Detail
Flows - History