Thanks for the quick response. Strange thing is, that if I go to subscribers – massive changes, is see:
Total in database: 363 (which is correct). But if I go to subscribers I only see one (myself).
I looked in the database and I found all subscriptions in wp_newsletter. wp_newsletter_*tables is nowhere to be found.
Now I can copy the email adresses from wp_newsletter and import them, but before I do that, I want to be sure that I won’t mess up everything… Any suggestions?