How to painlessly synchronize orders between Bitrix sites?

Question

1C-Bitrix

The essence of the problem. On the test site, the old Bitrix and BitrixVM were updated, all modules were corrected, everything was tested, everything is fine. How can I transfer new orders to the test site?
The cash desk is attached to the site with all the ensuing problems.
The most obvious way is to turn off the combat site for a day and update it and follow all the steps to fix custom modules, test, etc. But, the site will not work the whole day.

Who gets out of this situation and how? I would like to move seamlessly to the new site.

Answer 1

use git and migrations for custom edits
update at night

Answer 2

You do not need to turn off the site for a day to update. If you have tested and corrected everything on the test - you just need to write down what you corrected there - and within 15 minutes you will meet it - you already know where the problems were - you do not need to look for them, and if you forgot where they were - do the test again a copy, practice again, and write everything down on a piece of paper.