The EU General Data Protection Regulation

The GDPR is coming into force soon and I'm trying to sort out the consequences in general and for this blog in particular. With regard to this blog, over 2,000 people have signed up for email notifications, and presumably some of those people are from an EU country. Here's my question for any GDPR experts out there. All of the people who receive email notifications signed up on their own at some point. Do they now need to give fresh new permission in order to continue receiving these emails?