Software giant Microsoft let industry professionals begin testing its next-generation Internet Explorer (IE) web browser due for release by the end of the year. An "IE7 RC1" beta version of the world's most widely used web browser could be downloaded free of charge at the Redmond, Washington, company's website.

"Depending on your feedback, we may post another release candidate" of Internet Explorer 7, Microsoft general manager Dean Hachamovitch wrote in a weblog.

"Were still on track to ship the final IE7 release in the fourth calendar quarter."

Microsoft said in a release that it was "confident that developers and designers who optimize their websites and applications with this beta version will be compatible with the final version when it is released later this year."

The new IE was designed with improved performance, stability, security, and application compatibility, according to the company.

An English-based version beta IE was released on Thursday and would be followed in September by releases supporting other languages.

"Well continue with Arabic, Finnish, German, and Japanese as before but also add French and Spanish versions with this release," Hachamovitch wrote.

Microsoft said it planned to release the final IE version as a high-priority update.