A near-final version of the long-awaited Service Pack 1 (SP1) update of Vista is now publicly available.

The Release Candidate 1 (RC1) code is time limited and will need to be uninstalled when the full SP1 is officially released early next year.

Microsoft says the RC1 is for testing purposes only for organisations and people who are comfortable evaluating pre-release software.

The service pack marks an important milestone because many it is seen as bringing Vista to maturity. Vista users have effectively been bug testing the code for the past year, and many enterprises and other organisations have been waiting for the SP1 fixes before upgrading to the new operating system.

Many of the fixes have already been made available through the Windows Update service, but SP1 includes other less critical patches and tweaks.