I’ve removed Tabulate’s dependency on the REST API plugin, because that’s now been moved in to core WordPress. (Actually, that happened rather a while ago, but I’m slack and haven’t been paying enough attention to Tabulate this year; other things going on!)
I hope to get back to adding file-field support to Tabulate sometime soon. That’d be a useful addition for me. Also, the whole situation with Reports needs sorting out: better documentation, easier to use, support for embedding in posts and as sidebar wigets, that sort of thing.