Notice: The Regex below is outdated. Please visit the
WebKit bug page for better solutions that match more affected browsers.
Place the following into your .htaccess, httpd.conf, or virtual host .conf file:
<If "%{HTTP_USER_AGENT} !~ /(iPhone; CPU iPhone OS 1[0-2]|iPad; CPU OS 1[0-2]|iPod touch; CPU iPhone OS 1[0-2]|Macintosh; Intel Mac OS X.*Version\x2F1[0-2].*Safari)/i">
Header edit Set-Cookie ^(.*)$ $1;SameSite=None;Secure
</If>
For example, this page is using the same lines above to modify a unique cookie named "TestCookie". Open this page in Safari 12 and inspect the response headers to see how it behaves differently than Chrome 79.