Can I use the Zend Framework or PHP to determine which version of SSL my request is using?

You will need to configure it, but there is a way.

You can obtain the SSL/TLS version by writing SSLOptions+StdEnvVars in httpd.conf or .htaccess and $_SERVER['SSL_PROTOCOL'] in a PHP script in a valid directory.
However, SSLOptions+StdEnvVars is a setting that affects HTTPd performance, so you should use it only

Please refer to

• mod_ssl-Apache HTTP Server Version 2.2
• mod_ssl-Apache HTTP Server Version 2.4
• Go to https to see the environment variables in the centOS+apache+mod_ssl+mod_php environment -developer's directory

I also need to set it up, but there is a way.

You can obtain the SSL/TLS version by writing fastcgi_param SSL_PROTOCOL$ssl_protocol; in nginx.conf and setting it to $_SERVER['SSL_PROTOCOL'] in a PHP script in a valid directory.

Please refer to

• Modulengx_http_ssl_module
• Cannot retrieve HTTP_USER_AGENT with Nginx and FastCGI combination|OXY NOTES

If you are using mod_ssl in Apache, would it be possible to obtain it with $_ENV['SSL_PROTOCOL']?
http://httpd.apache.org/docs/2.4/en/mod/mod_ssl.html