123-Apps are installed using the databases included in your Hosting packages. This means that the Start Up package only allows for one app to be installed, as it only has one database. Business and Professional packages, however, have multiple databases, meaning that multiple Apps can be installed on one package.
You can choose whichever applications you want and not worry about compatibility!
When we install the applications, they will be done so using separate databases and installation folders to avoid compatibility issues.