In GeneXus, a Development Version is what in Software Configuration Management (SCM) is called a Branch, identifying with this term, the existence of different development lines.
One of the most common situations for using development versions is when there is a need to continue with the application's evolution (usually in the Trunk) while making maintenance fixes to an application in production (in a Development Version). What you need is that changes to either of them do not interfere with the other.
To create a new Development Version, open the Knowledge Base Versions tool window, right-click on any Frozen Version node of the tree which has no child nodes, and select the New Version option. Fill the New Development Version dialog and press Enter. The times it takes to create a branch is proportional to the size of your application. When a Development Vesion is created it is initialized with its parent's content.
Development Versions can be used: