Thanks for answerting. The non-Wordpress was developed from scratch, there is no existing importer.
The password of the users table to import was encoded with PHP function: password_hash(). This is why I ask the question how to change encoding in WordPress core.
I am facing the same problem than you now.
How did you solve it?
Me, I have to create custom post types equivalent of the non-wordpress website datas.
With my 15000 posts to migrate to WordPress, I’m trying to create the XML of them to import. Is it the good way?
Is there no existing extension to do this?