Drupal 8’s EOL (end of life) is just three months away on November 2, 2021. What does this mean?

No security patches will be provided for Drupal 8 after this date. There is also no extended support for Drupal 8 like there will be for Drupal 7.

You will truly be on your own. And with such a mission-critical piece of software, you do not want to be on your own.