This is version control for your model portfolios. It will make it easier for you to see which client is invested in each model and to keep track of who has recently rebalanced.
In future, when you make changes to a model portfolio a new version is created and previous version becomes closed to new business. All existing accounts invested in the previous version, as well as any instructions for rebalancing, phased investments, or regular payments, will remain the same until you choose to move them to the latest version, putting you in the driving seat.