A patch can be an upgrade (adding increased features), a bug fix, a new hardware driver or update to address new issues such as security or stability problems.

While most patches are free to download, ultimately the developer will determine which versions of their software will be updated for free (older releases of a program usually get fewer updates). In some cases, only registered users may get certain upgrades, and at other times the only way to upgrade is to purchase the newer version at a discounted upgrade price (and requiring a reinstallation of the program). Typically, a patch can be installed over the top of an existing program, but again this will depend on the supplier and the nature of the patch. Unless otherwise stated, patches and updates on this site are for PCs using English language settings.