Netscape 4 addressed the problem of Netscape Navigator being used as both the name of the suite and the browser contained within it by renaming the suite to Netscape Communicator. After five preview releases in 1996–1997, Netscape released the final version of Netscape Communicator in June 1997. This version, more or less based on Netscape Navigator 3 Code, updated and added new features. The new suite was successful, despite increasing competition from Internet Explorer (IE) 4.0 and problems with the outdated browser core. IE was slow and unstable on the Mac platform until version 4.5. Despite this, Apple entered into an agreement with Microsoft to make IE the default browser on new Mac OS installations, a further blow to Netscape's prestige. The Communicator suite was made up of Netscape Navigator, Netscape Mail & Newsgroups, Netscape Address Book and Netscape Composer (an HTML editor).