One of the more recent ones is interesting enough to blog about.
The subject is the holidays Outlook client can insert for you and how to remove them SERVER-SIDE.
Turns out that the old Exchange 2003 Utilities could handle this as a matter of course, but our new version did not until last week.
Here's the slightly longer technical story about what's happening: The Outlook holiday capability inserts client-side and helpfully includes the Category "Holiday"
That's good - because I have no idea what corporate or university user needs to know when Groundhog Day is (who put this list together, a grade school teacher?).
Looking at it in OutlookSpy you can also see why the terminology "Keyword" got applied to this early on and stuck.
Anyway, in Exchange 2003 the Sumatra Utilities used only the Keyword field, but to be safer in Exchange 2007 when we moved to EWS we also used a couple of hidden fields including Mileage (not as uncommon a technique among calendar applications as you might imagine).
So we expanded the concept of UNDO to be both for Category only or Category AND Mileage.
The good news, we fixed it so if you want to remove data server-side you can.
AND REMEMBER: We require keywords so that you do not accidentally remove everything in a calendar. But you WILL remove everything tagged with "Holiday." So be careful! You have been warned.