The UO Patch Notes section within the UOSecondAge.com Wiki has been recently revamped. It has been separated into individual wiki definitions per patch date for all official Ultima Online and Ultima Online: The Second Age patch updates that took place leading up to the release of Ultima Online: Renaissance. This should make the patch information on the Wiki alot easier to browse through and use for your ERA accuracy research purposes. I urge everyone who is not already familiar with this information to go over to the Wiki and check it out when you have a chance.
You can find it here: The Unofficial Ultima Online: The Second Age ERA Patch Notes