Coder58:
This should be selectable in the IDE, not in which directory is loaded.
The Arduino IDE already does have a UI for this (the version dropdowns in Tools > Board > Boards Manager). The problem is not a lack of UI but a problem in the functionality of the inner workings of hardware package updates:
- Occasionally failing to fully remove the previous version.
- Not gracefully handling the leftover folder after the above failure.
I believe the second issue has been recently addressed by the Arduino developers. You can try out the Hourly build and beta builds of the Arduino IDE available from the Downloads page so see if this is the case.
If you care to contribute any improvements to the Arduino IDE it would be welcome. You can submit pull requests here: