Hi Alex,
VCX 9.8.15 was released on Tuesday, May 10, 2011. The release did NOT add support for SIP trunk providers that require authentication instead of being accessed via a Trusted Endpoint. The release does contain the following enhancements:
Microsoft OCS & Microsoft Exchange Integration
Simultaneous Ringing
HP ProLiant DL360 G7 Support
The Central Management Console Web Interface can now display the replication status of primary/secondary pairs.
Scheduled Backups
ACD licenses are used dynamically instead of statically.
VCX now provides the administrator with the ability to selectively delete an individual future delivery message.
Voicemail Return Receipts
VCX extension numbers starting with 0.
The replication setup script was enhanced.
Voicemail to Email filename changes.
Background/Screen saver Image Enhancement
IPM Web Interface Enhancements
IMC VCX Enhancements
For further information regarding these enhancements and the VCX 9.8.15 release, please refer to the VCX 9.8.15 release notes.