Simple Links PRO is a totally new structure which is much more maintainable then the original add-ons. While it does include all the original functionality of the old Simple Links add-ons, it also includes many new and upcoming features.
The decision was made to kill the add-ons to open up a new maintenance release structure and allow for future feature enhancements. I still have a very small amount of funds allocated to support the old add-ons but it is very limited. For future compatibility and support I recommend upgrading to Simple Link PRO and removing any add-ons. Currently there are no migration requirements to keep everything intact, but I can’t guarantee upgrading will be seamless in the future.
To upgrade, simply delete any current Simple Links add-ons and install Simple Links PRO. At the time of writing all existing add-on features and settings will automatically transfer over.