Windows Installer 3.1 Final (build 1823) is now out of beta and available for download. For anyone using the RC (build 1812) you will need to uninstall this version before installing the final release. It’s up on Windows Update in case any of you didn’t notice.

Download: [b]Windows Installer 3.1 Final[/b] (2.46MB)

Notable New features in Windows Installer 3.1:
-New MinorUpdateTargetRTM property: Patch files can now target both the original release baseline and the latest service-pack-level baseline that is on the system.
-New MsiSetExternalUIRecord API: Packages that use an external user interface can now receive messages as records instead of receiving the messages as strings.
-New x64 and Msix64 properties: Packages can now use the x64 and Msix64 properties to indicate x64 processor-based operating system support.

I should have typo’d the title so it read “NEW Windows 3.1″. Ah, those were the days.

Source: Microsoft