Software is never perfect. Providing the ability to install multiple versions of ArcGIS Pro side by side would allow users to test new versions without having to completely uninstall and reinstall each new version.
To add further to this idea by @JesseTemplin2: because a lot of ArcGIS Enterprise functionality is dependent upon which version of Enterprise and ArcGIS Pro you have installed, having access to multiple versions is actually mission critical. For example, if you want to create (or migrate to) a parcel fabric in Enterprise, your versions of Enterprise and ArcGIS Pro must be compatible (see this documentation for Parcel Fabric versions Parcel fabric versions—ArcGIS Pro | Documentation), if either is out of sync, you will not be able to create and manage a new parcel fabric.
Upgrading versions of ArcGIS Pro is fairly simple and a relatively benign action, as it only affects the UX of the user on that machine. Conversely, upgrading an ArcGIS Enterprise environment can be very difficult, not to mention time consuming, and affects users across an entire organization, so typically Enterprise upgrades are not routine. In fact, I would surmise that many organizations only upgrade once a year, if that, and only after the first service pack has been released and has been production tested and found to be stable. For this reason alone, keeping your ArcGIS Pro and Enterprise versions in sync is not only difficult, but practically impossible.
For Enterprise managers like myself, we have to always keep a version of ArcGIS Pro that is compatible with our current version of Enterprise. That means we have to have a spare machine handy to host a downgraded version, or worse, have a downgraded version on one of our servers in the stack, which is not the best environment for running ArcGIS Pro, especially if your servers tend to be busy.
Please consider this idea not only for the important use described by @JesseTemplin2 but also for Enterprise functionality that GIS Managers need.
Thanks for the additional perspective @RandyCasey. I don't have any experience with ArcGIS Enterprise. I agree that upgrading is fairly simple, but chasing down a bug introduced in a new version takes significantly more time when having to repeatedly uninstall, reinstall, clone the python environment, install packages, etc. It doesn't happen often, but having multiple version on hand would save time when it does.
We have worked around it by setting up multiple virtual machines with older versions of ArcMap and Pro on them.
Our core machines are all on the same version and we (5 of us) all upgrade when our Project Manager says it is ok to do so. We don't want someone getting ahead or our core apps.
However, we often do work for partner cooperatives and often they are not up to current.
The virtual machines work pretty slick. We have three of them. So we are able to work in 3 different versions when required.
It is not always possible for a company to have all machines running the same version.
It would be really nice to have this option for us. I work for utility industry and because of the integration with third party ArcGIS Pro plugin, we cannot upgrade to the latest version of Pro due to compatibility issues with the plugin. However there are lots of people who do not need to use that tool at all and they can be on the latest version of Pro.
Just to keep this idea alive. We are running into similar problems as others and our concern relates to public safety/911. We have vendors that have not yet moved off of 2.9 so we are held back by the least advanced package. Having the ability to run differing versions would be very helpful.
I will like to be able to install multiple different versions of ArcGIS Pro on the same machine without having to install a 2nd operating system. This would be very useful when working with multiple different clients.
Adding to this, I am attending the GIS for Climate Action MOOC.
If I want to continue the course, I must upgrade to 3.2. However, my organization is not yet ready to upgrade to 3.2. This makes it frustrating as I have two things I want to do, but I would need two versions of pro.
Adding to all that has been said before, my organization manages two different ArcGIS Enterprise environments which, for governance and financial reasons, run on different versions (10.8.1 and 11.1) thus we are required, according to best practices, to use the versions 2.6 and 3.1 of AGP depending on the portal we need to work with. Therefore, it is essential to be able to use either one or the other version without having to deal with virtual environments or connecting to a remote server.
The issue is with the different python dependencies I think. If you do not rely on python to work properly with ArcGIS Pro, here is a dirty hack that worked last time I tried it: (at your own risk) Uninstall the latest version of ArcGIS Pro. Install the old version of ArcGIS Pro. Copy the install folder to a new directory. Update your ArcGIS Pro to the latest version. Now you can use the latest version as usual and keep it up to date. The old version can be started by navigating to the ArcGIS Pro executable in the old copied folder.
