Composite project using different version

Many goodies in FlowUI are yet to be developed/migrated. Is this a good idea to create a custom project with 2.X add-ons and 1.5.x as full stack project which would contain all UIs. I am unable to determine whether I would get any benefit from this. Suggestions and comments needed.

Unfortunately you cannot mix Jmix 1.x and 2.x modules in a single project. They use completely different set of dependencies.