Starting with version 7.1, Apple unified the implementation of non-roman script systems in a programming interface called WorldScript. WorldScript I was used for all one-byte character sets and WorldScript II for two-byte sets. Support for new script systems was added by so-called Language Kits. Some kits were provided with the system software, and others were sold by Apple and third parties. Application support for WorldScript was not universal, since support was a significant task. Good international support gave a marketing edge to word-processing programs such as Nisus Writer and programs using the WASTE text engine, since Microsoft Word was not WorldScript aware.