How do I save an executable as a variable in a *.mat?

Hi,

I am updating an application to use App Designer. One of the things we do in the Opening function is load a *.mat which defines a few structures and loads an executable (backend application). Specifically, the executable is saved as 'app' and is a COM.R140_application. This application type is out of date and I do not have the executable installed, thus when I load the mat file as is, I receive the warning:

Warning: Variable 'app' originally saved as a
COM.R140_application cannot be instantiated as
an object and will be read in as a cell. 

How do I save a different executable as a variable in the mat file? I will also be renaming it for obvious reasons...

Edit:

newAppName = system([path exename]);