Version Upgrade issues

Hi Everyone. I updated from version 12 to
ERPNext: v13.x.x-develop () (develop)
Frappe Framework: v14.x.x-develop () (develop).
Some of the functionalities are not working as they were on version 12.
For Example i have custom doctypes in integration module for biometric attendance. I t fetches data from biometric machines but the checkout time is been populated in both check in and check out field and also some other issue. so does anyone has a suggestion what i can do to overcome this a help will be appreciated.

hello, seems like you upgrade from 12 to develop which is not the same branch>
the best way to upgrade from 12 to 13 is to create clean version 13 bench production and create new site in it then restore your v12 site backup in it then run migrate

Thank you for your reply.
Will be working on it.

I created a fresh instance and also created a new site now what i have to do next.