Microsoft will ship a mobile version of Internet Explorer 7 inside Windows Phone 7 when devices ship later this year.
The mobile version, yet to be named, is a version between Internet Explorer 7 and 8 according to Microsoft corporate vice president Joe Belfiore. Speaking at MIX 2010 today Belfiore explained that the mobile browser takes HTML rendering code from Internet Explorer 7 which is optimized for low memory situations. Belfiore explained that some features have been back ported from Internet Explorer 8 and joked Microsoft could end up naming it Internet Explorer 7.5.
At present the browser within Windows Phone 7 identifies itself with the following user agent string: Mozilla/4.0 (compatible; MSIE 7.0; Windows Phone OS 7.0; Trident/3.1; IEMobile/7.0). Microsoft's Zune HD device on the other hand runs on IE6: Mozilla/4.0 (compatible; MSIE 6.0; Windows CE; IEMobile 6.12; Microsoft ZuneHD 4.3).
Microsoft is expected to announce its plans for Internet Explorer 9 on Tuesday at MIX 2010. According to sources familiar with the situation, Microsoft will release a developer preview of Internet Explorer 9.