Does the GDPR require use of a double opt-in subscription process?

When using a double opt-in subscription process, each new subscriber is required to confirm their subscription by clicking on an email that is sent automatically immediately after signup. This practice has many advantages in terms of deliverability because it allows you to check that the email address exists, and also confirms your subscriber's genuine interest.

However, the use of a double opt-in process is NOT required by the GDPR. While it is a good practice, it is not even mentioned by the GDPR.