Force to install a software on older macos version

Your best bet is a Virtual Machine using VMWare or Parallels, as historystamp suggested.

In most cases, if the app won't install on a given version of macOS, there's probably a good reason for it. I wouldn't be surprised if it failed to run even if you managed to get it running.

That being said, if you are determined to try, there are two free tools to help:

• unpkg

• Suspicious Package

Both will let you “extract” the contents of a package file. From there you can move them into the proper places and see if it runs.

The most frequent reason for software to only operate within a certain range of OS-versions is that they rely on frameworks, APIs and features that don't exist (or work poorly) in older versions of macOS, or the software is too old to work with the newer OS because the frameworks/APIs they need have been deprecated or removed.

Once the OS and the software diverge too much, there's little chance of making them play together again.