This works *sometimes* not always. It all depends on the patch.
The current client is 7.0.23.1 after this latest super fast patch.
Go to the directory that has your UO files. Normally it's something like C:\program files\ea games\ultima online
When you get into that directory find a file named Client.exe
Now copy that file, you can paste it right into the same directory. I make a folder called "Backup" and put the copies in there.
Rename the copied Client.exe to 7.0.23.1
Do this EVERYTIME there's a patch. You can tell what the current version is by loading UO and looking at the bottom of the login screen. Every time there is a patch do this. This way you'll start having a bunch of older clients saved.
Now, lets say that we're on client 7.0.23.1 and EUOX has already been patch. Everyone is super happy joy joy scripting away. Evil OSI patches to a new version 7.0.23.2... hisssssss... and lazy azz Cheffe is too busy gardening to bother with updating EUOx. What do we do??
Well, *if* we didn't stop the patch in time, or it's a mandatory patch, we normally have to wait it out. Now is the time to be thankful you backed up previous clients.
Just rename the current Client.exe (which is now version 7.0.23.2) to something like Client70232. Find that older version of the client that you backed up before and renamed to 7.0.23.1 and copy it back into the main UO directory and rename it to Client.exe
*Sometimes* that is all it takes and you can happily use the older version of EUOx. When Cheffe finally gets around to updating EUOx you can just remove that version of the Client.exe and rename the already patched one back to Client.exe and your good to go.
If I had posted this a few days ago you all would happily be scripting away right now like I am

*BTW: don't even ask if we will host these files. They are the exclusive property of Mythic and it's against the law to alter or maintain them. There is absolutely nothing wrong with you maintaining older version, but we can not host them.