Searching for ConvertDateTime works for me and gives 6 results.
https://docs.intersystems.com/results.html?docs%5Bquery%5D=ConvertDateTime
I think for 100% certain rollback a restore by @Ben Spead suggestion would be the way to go. While maybe if you were going back to IRIS 2024.1.1 you could just rename the install directory and install the old version I would not count on that working. I think things like journal files and IRIS.DAT get upgraded so you can not go back. You could have a mirror on the old and new version and move from the old to the new but you would still lose data since you can not mirror to a downlevel version - InterSystems IRIS Instance Compatibility
I would go to the WRC and ask them. Contact the WRC
Is it possible to define aliases per IRIS instance?
Looking at Aliases mentions the .iris_init but that is user wide.