Thanks pringlex for this news in the forums.
This from the InvisionPowerBoard website: We're pleased to announce that the final production release of 1.3 has been released to the download area.
This release fixes up the last few issues found in our pre release version. This version is fully supported by our technicians and if you require an upgrade, please go into your client center and start a new ticket requesting an upgrade. Please allow us a little extra time to complete your order as there is always a large influx of orders around a final release.
There are no skin or language changes from the pre final release. If you are upgrading from earlier versions of Invision Power Board, you may wish to log into your download area (use the same username and password as you use here) and view the "docs" section to compile a list of changed files.
If you are upgrading from 1.2, we recommend that you upload ALL of the IPB source files EXCEPT conf_global.php - it's very important that you don't upload that file from the download zip. You will also need to run "upgrade6.php" if you are upgrading from 1.2 - this can be found in the "Tools and Scripts" folder of the download zip.
Download: Invision Power Board 1.3
Download: Registered users upgrade
News source: Invision Power Board