+ - mbstring, fileinfo, mcrypt (optional)
+* PEAR packages distributed with Roundcube or external:
+ - MDB2 2.5.0 or newer
+ - Mail_Mime 1.8.1 or newer
+ - Net_SMTP 1.4.2 or newer
+ - Net_IDNA2 0.1.1 or newer
+ - Auth_SASL 1.0.3 or newer
+* php.ini options (see .htaccess file):