There is nothing wrong with improving, just make sure you have a frozen version that can handle the old cruft, some software is so stable that you wouldn't dare

There is nothing wrong with improving, just make sure you have a frozen version that can handle the old cruft, some software is so stable that you wouldn't dare to update, I have some software I made myself that does what it was designed to do and never give problems. However it does not keep one from ever going forward and design new ways of solving the same problems. So my advice would be freeze and move on.