Why the order dates haven't been migrated to Shopify?
Transfer of order dates depends directly on the server used by Shopify for clients’ stores. We move data format exactly the way it must be, regardless of the server type. However, the same date in the same format can be received by different shops in a different way.
Now, during the migration of orders to Shopify, the source shopping cart's time zone should be taken into account. Currently, this works with migration from Magento and WooCommerce.
In other words, when migrating from the Magento/WooCommerce to Shopify, we use the time zone from the source store configuration and transfer the order's date to the target store. Therefore, to have similar data, we recommend to set up the same time zone during store data migration in both source & target carts' configurations (e.g. UTC).
Note.This information isn't relevant to other shopping carts. In this case, the migrations are performed without any changes.