Windows CE 5.0 is a successor to Windows CE 4.2, the third release in the Windows CE .NET family. Windows CE 5.0 like its predecessors is marketed towards the embedded device market and independent device vendors. Windows CE 5.0 is billed as a low-cost, small footprint, fast-to-market, real-time operating system available for x86, ARM, MIPS, and SuperH microprocessor-based systems. Windows CE 5.0 builds upon previous Windows CE releases in its adoption of shared source. Since 2001 Microsoft have been steadily expanding the available Windows CE source tree with embedded system developers. Windows CE 5.0 is the most open Microsoft Operating System to date, though not all of the system is available under shared source agreements. Developers have the freedom to modify down to the kernel level, without the need to share their changes with Microsoft or competitors.