I have yet to find that as well. Only found a handful of the ones to be shutdown with a date.
Reviewed the latest LNMs (39-19) for all of the districts and the only one that bothers to mention anything is about Mequon. The next closed is Hawaii, and if we have questions about the status of the beacons to call someone. Some LNMs don't even have "DGPS" anywhere in the document.