Hi lippe ,
The only way to import the data is before updating the plugin as I told in previous posts.
We do not take any responsibility for the below action! Only for experienced users!
Please, remember to make a backup of your database before trying this!!!
As it's the only way, you'll need a previous copy of the plugin, you can get it here. At the bottom you'll find a dropdown to download old versions (I recommend he last before 1.5.0, this is 220.127.116.11).
These are the steps you must follow:
1. Deactivate and delete ATUM.
2. Install the old version.
3. Import all the meta you need.
4. Delete [db prefix]atum_product_data table
5. Update the option [atum_version] to the version you installed (i.e. 18.104.22.168) in the WordPress options table.
6. Update the plugin
Please, remember that the order of the steps must be the same as above
All the meta that I detailed in my previous post will be imported to the table during the ATUM's update.
Hope this helps.