Currently the reporting on program updates isn't possible. For us as a company we use programs extensively and need to be able to report on a program update. This field should be added along with other program information to standard reporting.
We have a similar need: Workfront informed me that we could use Note type report and filter on the Program in order to get program updates. This works, to a point, but the report type will not allow you to filter for "last update". As a workaround we filter the report on "Has Replies" = False and respond to the last update with the new update. This a new approach so we are yet to see if there are limitations. (eg maximum number of replies etc). Proper program update reporting would be very useful!
As your original idea is from 2017 I'd love to hear if you have come up with another solution.
