In a Tuesday announcement, Research in Motion (RIM) revealed that it had brought on a substantial upgrade to its BlackBerry PlayBook operating system, with one of the several additions to have come aboard being a native e-mail client for the tablet.

The upgrade, which is now available as a free 505MB download for RIM's last-year-released 7-inch PlayBook tablet, gives the device an email application. The email functionality was surprisingly missing on the PlayBook thus far, with the result that the tablet's users could send or receive e-mails only if they were connected a BlackBerry handset.

The much-delayed PlayBook software upgrade by RIM also gives the tablet the ability to run some apps which have been developed for devices based on Google's increasingly popular Android OS. Moreover, it also boasts the inclusion of some of the other new features that facilitate the automatic integration of information as well as messages from social networking sites - like Facebook, Twitter and LinkedIn - with its calendar, e-mail and contact apps.

In addition, the software upgrade will also give the BlackBerry handset users the ability to use the familiar keyboard on their devices as a physical keyboard for the PlayBook via a wireless connection.

However, despite the fact that the new upgrade for the PlayBook addresses some of the key issues in the tablet, analysts and market watchers are of the opinion that RIM has been a tad too late in releasing the update, which still does not bring all the features of BlackBerry handsets to the PlayBook!