The BlackBerry PlayBook is the underdog of the tablet world. It wasn’t so hot at launch, but later updates to the software got a lot of things right. Unfortunately for RIM, the tablet has only managed shipped a little under 2 million units. The tablet does have its fans though and RIM is continuing to take care of them.

The company that BlackBerry built announced today that the the PlayBook OS has been updated to version 2.1. It adds a number of new features to the tablet, but RIM thinks you will want to download the update for these three reasons:

Updated BlackBerry Bridge: Now you can view, respond and compose new SMS messages on their BlackBerry PlayBook Tablet when connected to a BlackBerry smartphone over Bluetooth®. You’ll also enjoy increased performance and speed of other BlackBerry Bridge functions as well. So you can do more, more efficiently. Txt away, my friends.

Email and PIM Enhancements: You’ve asked for it and we’ve delivered portrait support for email, calendar and contacts, giving you the option to use your tablet in either orientation to message. This will definitely come in handy for those of you who enjoy thumb typing in portrait mode like I do.

Improved Android Application Support: Includes Multi-Window Applications, Camera Support and In-App Payments. We all love a richer app experience, and with the improvements to the Android runtime, that’s just what you’ll get. Running the applications in separate windows allows you to multi-task between Android apps easier, and in-app payments will make it easier for you to enhance your app content. Game on!

The update also brings with it a number of enterprise features. PlayBook tablets can now enroll in the BlackBerry Mobile Fusion via a wireless connection. This means that IT administrators can now push updates over-the-air to everybody’s PlayBooks. It also now has full device encryption to protect sensitive and classified information that may be stored on the device.

PlayBook users should be receiving an update notification today telling them to upgrade to version 2.1 of the OS. If not, you can also just go to “Software Updates” under the settings menu to get the update manually.