Squid is a fully-featured HTTP/1.0 proxy with partial HTTP/1.1 support
The 5 series brings many new features and upgrades to the basic
networking protocols. A short list of the major new features is:

Squid 5 represents a new feature release above 4.17.

The most important of these new features are:

* Configurable helper queue size
* Helper concurrency channels changes
* SSL support removal
* Helper Binary Changes
* Secure ICAP
* Improved SMP support
* Improved process management
* Initial GnuTLS support
* ESI Custom Parser removal

Homepage:
http://www.squid-cache.org/
