I'm working on moving system user IDs from from an integer to a 160-bit value. Both of these values have existed in parallel for some time now, and there are only a few remaining uses of the integer value, and it is finally time to remove them.
However, the integer values have been used almost from the very beginning of the system, so there are at least a few important concepts that need to be updated. So I take it one step at a time.
I tackle big transitions through a potentially long series of easy to understand and stable stages. It's like putting together a puzzle. These transitions also help to stabilize and better document the system. Colby is designed to be "forever upgradeable", and this is a great challenge to ensure that it really is, even for system level models.