Each PowerBI version is incompatible with the prior one even if new features are not used. It enforces an organisation to move to the new version at the same time when files are shared IA PBIX file...
This is becoming a big issue for us. We often have users come to us with content they have created in the latest version of Power BI desktop, looking for it to be hosted on Power BI Report Server (Aug 2018). They are never happy to be told they will need to re-author the whole thing in an older version. Even if we could open the report in the Aug 18 version in a somewhat broken state, then fix what we need to, this would be a massive improvement on the current situation.
