Old documentation for ERPNext and Frappe Framework


I’m currently still using v 11 for ERPNext and Frappe Framework as I haven’t had plans for migrating soon.
But It seems that the documentation for those versions have been update to v 12 or 13.

Where do I find old documentation for v 11 features?
Why doesn’t the site documentation be categorized by versions so that users that are still in older version reference the old documentations.?

Thank you in advance