Font maker Bitstream Monday released version 2.1 of its free downloadable Bolt mobile browser. Version 2.1 adds tight integration with Facebook and support for HTML5 videos, as well as some Flash video support.

The Bolt browser uses Bitstream's server-side rendering of Web pages, making it a full webkit-based browser for feature phones. The browser offers Java and BREW versions as well, and is designed to run on most feature phones on the market. Bolt is also available for the BlackBerry, and can be configured as the default Web browser.

New Facebook integration in Bolt 2.1 allows users of the browser to work with Facebook instant messaging and to paste links directly to Facebook accounts. It also has built-in integration with Twitter. The HTML5 video support is in response to the growing number of Web sites that provide videos in the new format. Bolt 2.1 is also compatible with more sites using streaming Flash video.

Previously available as a beta version 2, the Bolt browser uses a server-side webkit engine to render Web pages then send them to the browser client on the mobile device, similar to Opera's Mobile Web browser.

"In just a few years it is expected that more people will be using the Internet on mobile devices than from desktop computers," said Anna Magliocco-Chagnon, CEO of Bitstream, in a statement. "Bitstream has engineered Bolt to maximize the utility of the Internet on mobile for end users, give handset manufacturers an important competitive differentiator for their mobile phone lines, and provide mobile network operators another way to compete for new users as well as to better manage the data usage on their networks."

Bolt 2.1 is built on Bitstream's ThunderHawk browsing technology and features video support; tabbed browsing, which provides users with the ability to simultaneously browse multiple websites and easily switch between them; widgets; split screen viewing; a download manager and integration with social networking sites.

Since it debuted in February 2009, Bolt claims to have a user base of nearly seven million users; 20% of whom are from India. The company also says it is adding one million users per month and that over 700,000 users downloaded the 2.1 Beta version.

Bolt 2.1 is available for download to Java devices and BlackBerry smartphones.