It hasn't been released, and is likely a long way off. The current working draft is at http://www.w3.org/TR/html5/. If you search for "what's new in html 5" you'll likely get many more articles than you can read.
Joined: Jun 05, 2010
Ok. So that means we are using Html4? I mean, suppose i create a file with .html extension, so, is that using html4?
Joined: Mar 22, 2005
So that means we are using Html4?
Who knows what you're using? Are you asking about a specific web page?
suppose i create a file with .html extension, so, is that using html4?
No, it's a file with an "html" extension. Nothing stops you from giving a PDF file an HTML extension, but that doesn't make it any kind of HTML. You create HTML 4 by using what the HTML 4 specification describes.
The word "Release" is not applicable. HTML5 is not software, it is a proposed standard for web software developers which will be submitted to international standards organizations in the next couple of years. Their adoption of HTML5 as the official standard is expected around 2020.
That said, all major browser makers strongly support HTML5 and have added many of the new HTML5 features to their current browser versions, or to their public betas. Since HTML5 is backwards compatible with previous versions of HTML and designed to fail gracefully in non-compliant browsers, you don't have to change any code you either have or will write in the future. If, however, you want to build better web sites, you should learn about HTML5's new features and begin using them today.