isSetSupported

The version number can be passed as text '1.1' or as a number 1.1.

Check the Host

if (Office.context.requirements.isSetSupported(RequirementsSetName, VersionNumber){ 
} 

if (!Office.context.requirements.isSetSupported('Excel API','1.1')) { 
   app.showNotification('Need Office 2016 or later'); 
   return; 
}