I found this sitting in my Drafts folder. I have no idea why I held back on publishing it, so I am doing so today (2024/4/8). My firm now has a content management system that will upgrade families to future versions, but I still think this is a handy node.
A huge shout out and many thanks to John Pierson for the Batch.UpgradeFamilies node in the Rhythm package. Have a large number of family files to upgrade to a new version of Revit? If you do not have a content management system that handles that chore for you, open the target version of Revit, fire up Dyanmo, pop in the Batch.UpgradeFamilies node, feed it a text string of the path to the root folder for your content, and select the Run button. You can then sit back and watch Revit background open, upgrade, and save every RFA family in that folder and all of the folders below it. Or, more likely, get on with some other task while that is taking place. The best part? It also deletes the backup files, leaving you with just the upgraded file.
It will tie up that version of Revit while it processes the files, but it will do it much faster than you could do it manually, and without the strain on your hands, wrists, and - most importantly - head. It does not get any better than that.