Can I downgrade my whole Revit installation?

[rachealhk]

I have, in this forum, learned that Revit drawings are not cross compatible with different versions of Revit. My client uses 2018. I have 2021. I understand I will need 2018 in order to work with their files.

The issue is -- I don't see any way to downgrade to 2018, or even to purchase/install 2018 separately from my current version. 2019 looks like the earliest I can get.

Is it correct that 2018 is simply unavailable, and I cannot work with this client, or am I missing a link somewhere?

[barthbradley]

Unfortunately not. You could export your project to IFC and that IFC could be opened in an earlier version. I doubt that'll work for you in this case.  

Backward compatibility of Revit with earlier releases of the software | Revit Products | Autodesk Kn...