After 6 years, Drupal 8 has reached the end of its life cycle. You can see all the information in the Drupal.org article:
It is recommended that all Drupal 8 users migrate to Drupal 9, as Drupal 8 will not receive any new security updates or bug fixes.
Meanwhile, the end-of-life of Drupal 7 is planned for November 2022. Although it was planned for November 2021, it was delayed due to the impact of Covid-19: https://www.drupal.org/psa-2020-06-24
So if you haven't yet considered moving to D9, it's time to migrate!