A second beta of the Firefox Web browser has been released.

Version 1.5 (beta 2) is now available for download and comes just a month after the first beta. A final release is expected by the end of the year.

Mozilla said however that the latest beta "does not contain any major new features since Beta 1". But that it did contain "improvements to automated updated system, website rendering and performance, along with several security fixes".

Although Microsoft's Internet Explorer has received more criticism for security holes than Firefox, the latter browser has also come under fire. In its semi-annual report about Internet security threats, Symantec said Firefox had more confirmed vulnerabilities in the first six months of the year than did Explorer.

Symantec said that doesn't necessarily mean that Firefox is less secure than proponents have claimed or that Internet Explorer is safer than many users believe.

Firefox has quickly become a challenger to the dominance of Internet Explorer. According to NetApplications.com, Firefox has 8.1 percent of the market, with Explorer on 87.2 percent. Apple's Safari, available only for Mac OS X, has 2.1 percent of users.

Mozilla officials said at Firefox's launch last October that they expected to gain 10 percent of the market by the end of 2005.

Microsoft, meanwhile, is testing the first beta of its updated Internet Explorer 7 with Web developers. Internet Explorer 7 promises improved security against viruses and spyware, including protection against so-called phishing attacks designed to steal users' personal data. It also replicates popular usability features in Firefox such as tabbed browsing.

Microsoft is expected to release the final version of that to the public by next spring.