Full change log of Windows Phone 7 Build 7.0.7390.0 March 2011 update is as follows:
OS version: 7.0.7390.0
Copy & paste. You asked for it—now it’s here. Just tap a word and drag the arrows to copy and paste it on your phone. You can copy text from emails, text messages, web pages, and Office Mobile documents, and paste it anywhere you can type. To learn more, see Copy & paste.
Faster apps and games. Nobody likes to wait. That’s why we’ve whittled down the time it takes for apps and games to start up and resume. It’s all part of our focus on getting you to the things you love, easier and faster.
Better Marketplace search. We’ve streamlined Marketplace search to make it easier to find specific apps, games, or music. Press the Search button in the Apps or Games section of Marketplace and you’ll see only apps or games in the results. Press Search in the Music section of Marketplace to search just the music catalog.
Other Marketplace improvements. We’ve improved the stability of Marketplace while you download apps. We’ve also improved the experience of downloading apps larger than 20 megabytes, upgrading from trial apps to paid apps, using a credit card with an address outside the United States, sharing links to apps via email, sorting Xbox LIVE games by release date, and creating an Xbox LIVE account from within the Games Hub.
Wi-Fi improvements. We now display your phone’s Media Access Control (MAC) address in Settings. (You might need this info if you try to connect to a Wi-Fi network that uses MAC address filtering. To learn more, see Connect to a Wi-Fi network.) We’ve also removed the limit on the number of Wi-Fi profiles that you can store and reduced the time it takes to start your phone if you’ve stored lots of Wi-Fi profiles.
Outlook improvements. We’ve improved the experience of viewing iPhone photo attachments you receive from a non-Exchange-based email account (such as a Google Mail, Hotmail, or Yahoo! Mail account), using the Global Address List (GAL) when connecting to Exchange Server 2003 using Exchange ActiveSync, and working with email display names that contain brackets (for example, "David Alexander [Contoso]").
Messaging improvements. We’ve improved the experience of receiving Multimedia Messaging Service (MMS) messages if your phone uses a PIN-locked SIM.
Facebook integration. We’ve improved the experience of syncing Facebook accounts.
Camera improvements. We’ve improved the stability of switching between camera and video modes.
Audio improvements. We’ve improved the experience of using a Bluetooth headset to make calls when you’re playing music or videos.
Other performance improvements. This month’s update also includes software from several phone manufacturers that improves the performance of specific models. Naturally, if you don’t have one of the affected models, we won’t install this portion of the update on your phone.
In order to update your Windows Phone, you will need to connect it to your PC or Mac via USB cable, start Zune for Windows or the Windows Phone 7 Connector for Mac, depending on the kind of computer you have, and then simply follow the onscreen instructions to update your phone.