Google has announced that it will no longer support older versions of various browsers on a variety of it's web based products such as GMail, Google Calendar, Google Talk, Google Docs and Google Sites. And the browsers which won't be supported any more by Google any more are Internet Explorer 7, Mozilla Firefox 3.5 and Safari 3. The announcement does not say anything about Google's Chrome browser.
However, Google has given it's users time till August 1, 2011 to upgrade their browsers to the latest versions but after August 1, 2011 users who will still be using the above mentioned versions of their browsers may have trouble in using regular Google applications such as GMail, Google Talk on Web, Google Docs, etc. GMail features such as desktop notifications & drag-and-drop file upload need browsers that support HTML5. So, users on older browsers may not get to experience such features anymore after August 1.
Here is a quick know-how about Google's new Browser support cycle policy:
All current and prior major releases of browsers like Chrome, Firefox, Internet Explorer and Safari will be supported on a rolling basis.
Each time a new version is released, Google will start supporting the update and stop supporting the third-oldest version.
So, in order keep using all the advanced and useful features offered by the various products in Google, make sure you upgrade to the latest version of the web browser you are using. Here are the download links for getting the latest versions of various web browsers: