how to run two different generations of the same program on Mac

[Boulez]

Hi,

Could anyone advise on how to run two different generations of the same program on Mac (on Catalina 10.15.7)?

A developer is working on a math intensive application for me which involves a lot of complex functions and number/data checking from one version to the next as each version is brought forward. Some years ago (prior to Apple signing and notarization) we worked on a similar project, and at that time I could run two or more consecutive versions (3.1, 3.2, 3.3…) side-by-side on a single machine. It was therefore possible (and relatively easy) to check the integrity of the data—so it was correct and consistent for each step updating the new software.

Is this is no longer possible? It seems short-sighted on Apple’s part if that’s the case. Although I guess the present policy would push specialist developers to purchase more than one machine?

One workaround I’ve tried: create an extra user account; install the latest version for myself (as administrator) and the prior version logged in as the extra user. But as far as I can see the two users ‘see’ the same software—whichever version I install, both users see the same software. Is this correct or am I doing something wrong?

Thanks for any responses. (Apologies in advance I might be slow to acknowledge)

 

[Nermal]

Nothing in the OS prevents this: I do it relatively often myself. You've mentioned a workaround, but you haven't said what the actual problem is.

 

[Boulez]

Nothing in the OS prevents this: I do it relatively often myself. You've mentioned a workaround, but you haven't said what the actual problem is.

Thanks for reply.

When I install the program it automatically and apparently necessarily overwrites the existing program. My understanding is that by checking it through the Apple protocols (which is necessary for me to be able to receive from the developer and successfully run the app)—there’s no way to install it but that it overwrites. Is this wrong? Or specific to later generations os Mac OS?

I am primarily a PC user, so my understanding of the Mac protocols is limited.

 

[Nermal]

OK, so that's the installer to "blame", rather than the app itself. I would try this:

- Install the old version
- Right-click its icon and choose Compress, so that you have an archived copy of it
- Run the new installer to update the app to the latest version
- Decompress the archived copy, in a different folder

Are you then able to run both at the same time?

Whether this works or not depends on whether the installer is only updating the .app itself, or whether it's scattering other files throughout the system.

 

[Bigwaff]

Could you not simply rename the existing application in the Applications folder with a version number or something, and then install the new version with the installer? I do this quite regularly to have older versions of applications available.

 

[Fishrrman]

I do this the "Fishrrman stupid user"™ way (that's a self-descriptive phrase):

I give one of the apps a SLIGHTLY MODIFIED NAME.

Then they can BOTH reside in the same applications folder and may even be able to run simultaneously.

For example, in my applications folder I have two versions of Apple's "TextEdit" app:
"TextEdit" (version 1.20)
and
"TextEdit 1.6" (old version from years ago, that I still like).

Both will launch and run side-by-side on the desktop.

This may not work for EVERY application.
But you won't know unless you give it a try.

 

[Slartibart]

one caveat: if the program uses an installer probably some frameworks/libraries or other dependencies will be additionally installed. Using @Fishrrman´s suggestion, you can rename the program easily after install, BUT: if the next installer overwrites essential dependencies with incompatible versions you will run into problems.
Solution in this case: ask the programmer to create an app which include the required depencies - collateral effect: you can install by drag&drop. 🤓

 

[zevrix]

As others already said, nothing prevents you from doing that. Just rename the existing version before installing the new one (or move it to a separate folder). I'm only wondering why the developer himself didn't provide you with this simple solution right away.

 

[FreakinEurekan]

The real answer is - check with the app developer. It's up to them, not Apple, to determine if or how to run multiple versions simultaneously.