As the title says, I'd like to suggest to (re-)introduce the possibility to save an ArcGIS Pro project in a previous version.
I know - all users should always work with the same version to prevent compatibility problems. BUT: sometimes two different offices work together on the same project and those two offices have different versions installed for all their employees. Thus a single employee cannot simply use the same version as the employee of the other office. The compatibility problem is guaranteed - either between the two offices or within one office.
It should be possible to agree that project XY is created with ArcGIS Pro version xy. Those who are already a version further would simply need to save the project in the agreed version. Problem solved.
Therefore I'd like to suggest to re-introduce the possibility to save the project in a previous version of ArcGIS Pro.