After I did data migration on magento2. We implement the new function on the Magento dev website. The current Magento 1 site is, the live site and running.
So, I would like to know: " How to migration data again on dev site from the live site after finished work on dev site?"
Do we need to do the migration again with null database or something?
If you have placed orders on dev site for testing then your increment ID is updated so you need to do the migration again on Fresh Magento 2 site and then you have to merge the customer, order, and product on dev Magento 2 site.
After then create the clone of Magento dev site (clone 1) and do the testing on clone 0 sites.
if all works perfectly.
You can do lunch in the following steps
Yes, You need to migrate data again on Blank database and you can use the same code-base on new migrated database.
