Facebook does not recognize Safari 17.6

Hi,

When I open notifications on Facebook I get a message that my Safari 17.6 is not recognized. Apparently I have to download Safari 18. My operating system is OS Monterey. How can I download Safari 18? I bought my laptop new in 2017 from Apple. I know that it cannot be upgraded to a newer OS, and I am fine with Monterey, I just need Safari 18. Can you please let me know if there's a way to download it?

Thank you!