Microsoft announced at the TechEd conference some enterprise email features on its upcoming Windows Phone 7 update dubbed Mango, said to be released on May 24.

Other than the features earlier mentioned, including Bing and Facebook integration, and visual voicemail support, Microsoft revealed some fine changes to the email app and hub, which include pinning email folders, conversation view, server search, and Lync mobile communications capabilities.

The Mango update allows users to pin email folders or RSS feeds on their Windows Phone 7 devices’ homescreen.

In addition, users now have threaded emails, allowing users to follow their emails in conversation view.

With server search enabled, users have the ability to search email servers for old messages not available on their phone’s internal memory, giving them the ability to access entire email archives, not just those synced on their devices.

Lync Mobile integration will be available as a downloadable Marketplace app, allowing users to see the presence of co-workers and set their own status according to availability.

Moreover, system administrators will find comfort with more security upgrades to Windows Phone 7, which include more complex alphanumeric passwords, and support for hidden corporate Wi-Fi networks.