The AmigaOS look and feel, though still largely based on the earlier 3.1 release was revised somewhat, with an improved user interface based on ReAction, improved icon rendering and official support for true color backdrops. These releases included support for existing third-party GUI enhancements, such as NewIcons, by integrating these patches into the system. The 3.5 and 3.9 releases included a new set of 256 color icons and a choice of desktop wallpaper. These replaced the default all-metal gray 4/8 color scheme used on AmigaOS from release 2.0 to 3.1. The main improvements were the introduction of a program start bar called AmiDock, revised user interfaces for system settings and improved utility programs.