During its supported lifetime, software is sometimes subjected to service releases, patches or service packs , sometimes also called "interim releases". For example, Microsoft released three major service packs for the 32-bit editions of Windows XP and two service packs for the 64-bit editions. Such service releases contain a collection of updates, fixes, and enhancements, delivered in the form of a single installable package. They may also implement new features. Some software is released with the expectation of regular support. Classes of software that generally involve protracted support as the norm include anti-virus suites and massively multiplayer online games . A good example of a game that utilizes this process is Minecraft , an indie game developed by Mojang , which features regular "updates" featuring new content and bug fixes.
Digraph . A pair of signs or symbols (two graphs), which together represent a single sound or a single linguistic unit. The English writing system employs many digraphs (for example, th, ch, sh, qu, and so on). The same two symbols may not always be interpreted as a digraph (for example, ca th ode versus ca th ouse ). When three signs are so combined, they are called a trigraph . More than three are usually called an n-graph .