I have some drupal 6 sites sharing its users table. Now I will add a new site using drupal 7, but users table structure (and password) changed.
Which is the best way to keep just one users table (username, uid, password, ...) accross drupal 6 and drupal 7 sites? I was thinking of using OpenID and configure one site just to act as a server and all the others as clients.
Any hint is wellcome.