How to update new release of erpnext

How can i update new releases of erpnext to v12.1.8.

You can update the Frappe/ERPNext using
bench update

or use below commands to take a latest pull of respective branch,

sachin1@sachin1:~/workspace/v12/frappe-bench$ cd apps/erpnext/
sachin1@sachin1:~/workspace/v12/frappe-bench/apps/erpnext$ git branch 
* develop
sachin1@sachin1:~/workspace/v12/frappe-bench/apps/erpnext$ git pull upstream develop 
remote: Enumerating objects: 298972, done.

I tried this (with version-12 branch though) after bench update had failed. The git commands run through without any issue but the ERPNext instance is not available afterwards (Internal Server Error).

Is there anything else you need to run after the git pull commands?

Edit: my original problem went away but I’d still like to learn how to update bench/frappe/erpnext without bench commands just in case