How do I reinstall an older version of Messenger on a 2019 MacBook Air running macOS Big Sur 11.7.10?

I have an MacBook Air running Big Sur 11.7.10. I received a message that Messenger was being updated and to press button to update. I did and downloaded update. Now I received a message that my MacBook Air will not support the new version ...... but my old Messenger has been deleted! The icon is grayed out with a line through it. What do I do? How can I download an older version of Messenger?

[Re-Titled by Moderator]