WP4 - WordPerfect 4 Document
Once known as the most popular word processor available, the WordPerfect Corporation released WordPerfect 4 in 1985 using the file extension .WP4 to store generated files. With the step-up release to version 4.2 in 1986 which included paragraph numbering which is important to law offices, and footnotes which are important in both law offices and academia, WordPerfect surpassed the current market leader, WordStar for dominance in the word processing market.
WordPerfect 4.2 is a DOS based application which may be supported by Windows XP, Vista, Windows 7 and Windows 8 in DOS compatibility mode. WP4 documents may be opened by WordPerfect version 4.2 and later. Many third party word processors such as Microsoft Word and OpenOffice as well as the current version of WordPerfect now owned by Corel allow older versions of WordPerfect documents to be imported directly into modern files without the need for an external conversion utility.
While WordPerfect Corporation retained ownership of WordPerfect, and later, WordPerfect Office which included a bundled spreadsheet and database packages until 1994, it was purchased by Novell and later by Corel who retains current ownership of WordPerfect. All later versions of WordPerfect for DOS as well as WordPerfect for Windows retain the ability to open .WP4 documents and files.