I started getting warnings in FF: Some cookies are misusing the recommended “sameSite“ attribute

I tried various methods, which mitigated some of the problem, but I continued to get admonished about my cookies.
It looks like people on older versions of PHP are getting the warning and resorting to a hack. We're on the verge of upgrading so I didn't want to have any of that.

It looks like an .htaccess one-liner is solving the issue for me:
Header always edit Set-Cookie (.*) "$1; SameSite=Strict; Secure"