From Daniel Spreadbury at the Sibelius website:

"We're delighted to announce that we have today made available Sibelius 6.1, which is a free download for existing Sibelius 6 users. All new copies of Sibelius 6 shipped in the UK and US from today will be Sibelius 6.1. Today also marks the availability of the localized versions of Sibelius 6.1 in French, German, Italian, Japanese and Spanish. More information about these versions will be available on this web site from Tuesday 20 October. In the meantime, contact your distributor or favourite reseller in your country for information about availability of Sibelius 6.1 in your language. Demo versions of the localized versions of Sibelius 6.1 will be available from this site later this week. "

There's a PDF entitled "Changes in Sibelius 6.1" at:

Quote therefrom:

"4.12 Playback Devices
Sibelius now fully supports the ARIA sample player used by the new version of Garritan Personal Orchestra (GPO4), including automatic loading of sounds without showing a progress bar, just as is possible with the built-in Sibelius Player."