Using Pro and Personal for diffrent Projects


i´m about to team up with somebody who has a pro-licence for a commercial product, but has developed the teamproject so far with the free version. I also only own the free version.
Is it possible for him to have both versions installed on the same computer (the upgrade he did one day ago upgraded ALL installed versions) and work on seperate projects with seperate versions/licences?
I know it´s not allowed to work on the same project mixing personal and pro. I also found some older threads which quote parts of the EULA which stated that you can´t use both versions at the same time at all, but they are quite old.

In the current EULA i did not find anything regarding this issue so far.

Thanks in advance

It’s the very first paragraph in Section 2 of the EULA:

"Unity Personal Restrictions. You acknowledge and agree that as an express condition to the license rights granted under Section 1, you are not permitted to combine or integrate in any manner any Licensee Content developed with Unity Personal with any Licensee Content developed simultaneously with Unity Pro. For the avoidance of doubt: (a) if you are a permitted user of Unity Personal, you may commence a project using only Unity Personal and subsequently upgrade all (but not less than all) of your licenses to Unity Pro and the applicable Unity Pro Add-On Products, and (b) any user of the Software may use content licensed from third parties regardless of the version of the Software that was used to develop such third party content. You acknowledge and agree that Unity may tag Licensee Content created with Unity Personal with an identifier to prevent such a prohibited combination of Licensee Content. "