Neverending list of messages sent to this subscriber, GDPR problem?

phpList maintains a list of all the messages sent to each individual subscriber, for example

Campaign Sent Viewed Response time
Christmas Party 27 Dec 2020 23:12:07 28 Dec 2020 10:26:04 11 hours 13 minutes 57 seconds
... and another 102 lines stretching back to 2014.

The GDPR requires that personal data must only be kept as long as is necessary, and I think this list needs to be trimmed so it only holds the last six months worth or so. I cannot see an option to remove old entries from the list. I may be able to do this via a custom database query but I want to avoid this repetitive task. Am I overlooking something?