Aurora is a step in the development of a new Firefox version, followed by beta version(s), followed by the full release version.

To check which version your have currently installed, do the following:

1. click Help > Troubleshooting information
2. on the new display, next to ""Build Configuration", click the link shown (the link should be: about:buildconfig)
3. on the page with the title about:buildconfig, click the link next to "Built from"
4. this display should show "FIREFOX_5_0_RELEASE FIREFOX_5_0_BUILD1" if it is the Firefox 5 Release version released today; mine is highlighted in yellow.

What does yours show on that last page?

If needed, you can update by one of the following:

• clicking Help > About Firefox > click the Check for Updates button
• Download and install the full version
  • Download link: http://www.mozilla.com/en-US/firefox/all.html
  • See:
    • Installing Firefox: http://support.mozilla.com/en-US/kb/Installing+Firefox
    • Clean Install (if you wish) - do not delete your personal data when un-installing the old version (ie, do not check the box to remove personal data): https://support.mozilla.com/en-US/kb/Basic+troubleshooting#Clean_reinstall
    • Baking up your Profile (for protection of your personal data): https://support.mozilla.com/en-US/kb/Backing+up+your+information

See also:

• http://www.mozilla.com/en-US/firefox/channel/
• https://developer.mozilla.org/devnews/index.php/2011/04/07/new-development-channels-and-repositories-for-rapid-releases/

Firefox Aurora is a developmental version which is basically a testing ground for Firefox. Here is how the development cycle works in order from first release to final release:

1. Firefox Nightly
2. Firefox Aurora
3. Firefox Beta
4. Firefox Final Release

Firefox Nightly is the cutting-edge "newest" Firefox you can have. However, it is extremely unstable, and I don't recommend downloading it unless if you're willing to risk crashing your computer. If you want to download it, however, do so on a computer in which it is not top priority. Download link here: Firefox Nightly Download

Firefox Aurora is the next "step" in development of Firefox. It is not a separate web browser. It is the in-between step of Firefox Beta and Firefox Nightly. Although it is more stable than Firefox Nightly, it may still crash often. So don't download Firefox Aurora (remember, it's still Firefox) unless if you are willing to deal with some crashes. If you want to download it (if you don't already have it), you can download it here: Firefox Aurora Download

Firefox Beta is the next "leap" in development. It is much more stable than Aurora, but is still not the final version yet. If you want to download Firefox Beta, click here: Firefox Beta Download

At last, the final version is released to millions of users today. (If you have Aurora and not the final release, and you want to download the final release, click here: Firefox Final Release Download)

Hope this helps!

Oh, and also, you can check your version number and whether you are on Aurora or Release version by clicking the Firefox button (or help) and clicking "About Firefox." Then you will see "you are currently on the _____ channel (release, beta). If you are on your desired channel, then you are done! If not, and if you want to download another version, follow Helper7677's steps on the first comment.

Hope this helps (again)!