Since Bluetooth APIs were introduced into Windows (we are talking about the desktop OS here, not Windows CE / Windows Mobile / Windows Phone) there have been numerous updates and changes. Confusingly not all of these have been in Major updates or service packs but some changes are implemented in OEM only packages. We have been working on the 32feet.NET library to ensure we continue to support the new features in the Microsoft Bluetooth stack. There are a number of useful resources which describe the changes. Firstly Alan McFarlane, who has done a lot of really great work on the 32feet.NET library, has put together a detailed description of the changes in Windows 7 including a dive into the native header files. As you’ll see one of the main area of changes is the support for Bluetooth 2.1 which introduces new authentication methods. You should read Alan’s full article.
I also noticed that Microsoft have published a new FAQ on Bluetooth support in Windows. Interestingly this covers the entire history of Bluetooth on desktop Windows showing which releases implemented which Bluetooth versions. It goes into some depth on developing drivers for Bluetooth devices too – for example if you implement the Device ID profile you are able to integrate into the new Device Stage UI in Windows 7. The Download is a Microsoft Word 2007 document:-
http://download.microsoft.com/download/9/c/5/9c5b2167-8017-4bae-9fde-d599bac8184a/Bth_FAQ.docx
In The Hand Ltd 