The Rich Text Format (often abbreviated RTF) is a proprietary document file format with published specification developed by Microsoft Corporation from 1987 until 2008 for cross-platform document interchange with Microsoft products. Prior to 2008, Microsoft published updated specifications for RTF with major revisions of Microsoft Word and Office versions. Most word processors are able to read and write some versions of RTF. There are several different revisions of RTF specification; portability of files will depend on what version of RTF is being used.