Getting Squid
Squid is available in several forms (compressed source archives, source code from a version control system, binary packages such as RPM, DEB, and so on) from Squid's official website, various Squid mirrors worldwide, and software repositories of almost all the popular operating systems. Squid is also shipped with many Linux/Unix distributions.
There are various versions and releases of Squid available for download from Squid's official website. To get the most out of a Squid installation its best to check out the latest source code from a Version Control System (VCS) so that we get the latest features and fixes. But be warned, the latest source code from a VCS is generally leading edge and may not be stable or may not even work properly. Though code from a VCS is good for learning or testing Squid's new features, you are strongly advised not to use code from a VCS for production deployments.
If we want to play safe, we should probably download the latest stable version or stable version from the older releases. Stable versions are generally tested before they are released and are supposed to work out of the box. Stable versions can directly be used in production deployments.