Watermark remains after upgrading

I have upgraded a newly created book to ‘self-publisher’ sub level and re-exported an EPUB to remove watermarks and although the main full-page Pressbook advert has gone, I am still left with ‘This book was produced with Pressbooks’ on the copyright page. Any ideas how I remove this line?

Thanks

Hi @asianshorts that line appears by default in all exports unless explicitly turned off as a part of core Pressbooks: pressbooks/class-epub.php at dev · pressbooks/pressbooks · GitHub. We’re working on a bug fix to turn it off for exports produced on pressbooks.pub in all books with paid subscriptions. Hope to have an update for you shortly.