My iOS development environment is exactly as I left it, but the code is not in good condition. I had converted the Dropbox screen to use iCloud as an alternative data source, but had not tested it. Unfortunately I no longer have a copy of the code that worked with v1 of the API.
I will leave this on hold, while I get on with the more important task of updating the PHP code on the web server. There are also a few minor changes to be made to the Android client.