To open this spreadsheet you'll need a newer version of Numbers
I just tried to open an important spreadsheet on my iPad 3 running iOS 9.3.5 and got this message. I apparently opened the spreadsheet on my mac with a newer version of numbers. Normally I only use the file on my iPad so I don't open it on the computer. I guess I got careless because for a few years Apple has been better at retaining backward compatibility with Numbers files. Now they've decided that's not important.
There is no higher version of numbers available for the iPad and 9.3.5 is the highest version of iOS available.
Is there a way I could revert to an older version of the spreadsheet? The file is in iCloud and I know old versions are retained. On the Mac there's a "Revert to " menu item, but that doesn't seem to be available on Numbers on the iPad. If I revert on the mac and save it'll probably just save the reverted file in the new format.
I also have Time Machine backups but finding iCloud files will be tricky.
iPad, 9