Why only the 7B version? Would there be possibility to add support for the 13B as well if someone has enough RAM to run it?
The 7B version was a decent enough starting point in terms of what it can answer (and way fewer folks can run a 13B on their machine).
If you really want you can just replace the 7B model file with the 13B one under the ~/.cache/gpt4all directory on your device and it should just work.