Windows Mobile 6.5 is built on a customized version of Windows Embedded CE 5.X. Windows Mobile 7 is likely to be built on Embedded CE 6.X. But there’s another new version of Windows Embedded Compact (formerly Windows Embedded CE) in the works, codenamed “Chelan,” shown at TechEd 2009. Chelan, also known as Windows Embedded CE 7.0 is the successor to Microsoft’s Windows Embedded CE 6.0, and is on track to be released to manufacturing in 2010 (just like “Quebec,” which is the next version of Windows Embedded Standard, a k a XP Embedded).

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