Microsoft Internet Explorer 5 is a graphical web browser released in March 1999 by Microsoft, primarily for Microsoft Windows, but initially with versions available for Apple Macintosh, Sun Solaris, and HP-UX. It was one of the main participants of the first Browser war. Its distribution methods and Windows integration were involved in United States v. Microsoft. It was superseded by Microsoft Internet Explorer 6 in August 2001, although IE5.x remains the last version for Windows 3.1x, Windows NT 3.x, and Windows 95. Version 5.0 was included with Windows 98 Second Edition, and 5.5 with Windows Me when they were introduced. The Mac edition came out in 2000 and was included with Mac OS X, and the Tasman layout engine. IE5 presided over a large market share increase over Netscape Navigator between 1999 and 2001, and offered many advanced features for its day. In addition, it was compatible with largest range of OS of all the IE versions. However, support for many OS quickly dropped off with later patches, and Windows XP and later Windows versions are not supported, because of inclusion of later IE versions.