ARCHICAD can back-save project files in the previous ARCHICAD version. As example if you have an ARCHICAD 21 project, you can save it back to ARCHICAD 20 but not to ARCHICAD 19.
- Use File > Save as…
- In the Save dialog box, choose ARCHICAD xx Project from the Save as type list.
- You will get a warning:
- Click on ‘Save Anyway’
Before back-saving a project, always check the Migration Guide: