Twig 2.0 was released in January 2017 and Twig 3.0 in November 2019, almost 4 years ago. I think it's time to end the maintenance of Twig 2. The end of life will be end of December 2023.
If you haven't upgraded yet, you can read the Twig deprecated page for Twig 2 to get more information about what changed between Twig 2 and Twig 3 and how to upgrade.
As a consequence, Symfony 7.0 won't support Twig 2.