I saw the thread closed March 18, 2019 about saved files in PR9 that aren’t compatible in RP8 (How to save an axure 9 file to open in axure 8). However no one clearly asked or answered the following question:
Does RP9 have the feature/capability to purposefully save out a backwards compatible file for RP8?
Axure RP 9 does not have a feature to save out a file that is compatible with Axure RP 8. For that reason, if you’re upgrading from Axure RP 8 to Axure RP 9, we advise saving a copy of the Axure RP 8 file if you ever need to reference it in the future.