I see there is a new endpoint to delete priorities. I have it working in my app just fine. However, I get the following error while testing:
- Status: 400
- Error Message: Returned if the request isn’t valid.
- Actual Error Message Returned: The newPriority has to be provided.
So basically, things are working correctly. However, providing a new Priority value isn’t required so this functionality should not break if it’s not provided. I know other endpoints will just default to whatever the default is. For example, I believe if you delete an Issue Type Scheme it will automatically assign the default Issue Type Scheme in the system.
NOTE: If this is a bad example, I’m just going off the top of my head for an example. Regardless, I know for a fact that this functionality does occur in the system for various endpoints.
Anyway, I know this is experimental so maybe the functionality has not been completed quite yet. But I wanted to follow up to see if 1) this is going to be the desired behavior or 2) will an update be done to either make a replacement value required or allow the process to complete if a replacement value is not provided.
By the way, much needed endpoint as I have a cloud app and have several clients that do multiple acquisitions each year and when we migrate/consolidate their instances, they quickly accumulate Priority and Resolution values so being able to bulk remove the unwanted values is a great addition to our tool that is used to do massive cleanups quickly. 
P.S. I also see a new endpoint for retrieving all Priorities. The bonus with the new endpoint is we can capture the instance’s default Priority value (if set). This would allow my app to capture the default and automatically pass it into the delete endpoint. In short, loving the new updates!