UUID [0] is a concept, not an implementation. You can implement UUID in any language. It's like an algorithm.

[0]: https://en.wikipedia.org/wiki/Universally_unique_identifier

UUID's are always possible, you're thinking of the IDFA (IDentifier For Advertisers), which is tied to the device. If you generate a UUID and store it locally you should be able to maintain identity, at least until the user deletes the app.