Thanks to Chainfire for pointing me to this.
Applications that were made for Windows Mobile 6 are compatible with Windows Phone 7 Series. The interface of the new mobile operating system has been changed though, so the user interface for these applications will have to be changed as well.
"So there is no reason why programs written for Windows Mobile 6 cannot run on the new version of the OS", said Maarten Sonneveld of Microsoft Netherlands to Tweakers.net. "The interface is complete different though, so the applications will have to be changed somewhat before being ready for Windows Phone 7 Series".
It is still unclear how developers can port their user interfaces to the new version of Windows Mobile. Microsoft will only disclose how applications can be developed and distributed at their developer event Mix2010.
Microsoft announced it’s new OS on Monday afternoon at the Mobile World Congress in Barcelona. The OS is primarily aimed at synchronisation and integration with Microsft-services like Windows Live, Bing, Zune and Xbox Live. Aside from those Windows Phone 7 Series can also synchronise with Google-accounts and facebook.
This could potentially be very good news for developers on the WM platform, though we will only really know when MIX2010 comes around.
Would you prefer a complete breakaway from WM6.5, or would you like to see your old software working on WP7?