Fix the work of the site - a web programmer

Run tasks on the site:
Refresh the banner, comb through forms - fix which dont work (there should be a notification to the mail)
Upgrade WP from 5.4.5 to 5.7.1
Update PHP from 7.1 to 7.4 (or the latest stable version)
To test the site on the Safari browser.

Detailed TK
docs.google.com/document/...