To update the reNgine to the latest version use the following commands:
Stop if reNgine is running
Get the latest changes, make sure you're in
This should pull any latest changes in reNgine from a master(stable) branch.
Since you already have certs built, you can skip building certs. The next step would be to build reNgine once again.
If no error appears, you're good to go.
happy reconnaissance :-)