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.
I tried to test my new app on a Pixel XL emulator, running on a PC with fairly modest specs. But it was so slow that it was unusable. It was also illegible, but I did not really get that far.
I was not going to order my new phone until my birthday, but the Amazon website jumped the gun last night. I am glad it did. I also have a Fire 7 tablet that I could use at a pinch, but I think I will wait.