Two
The first call will be on August 16th, 2011 at 11:00 AM EDT and will cover "Upgrading IBM Sametime Community Servers: 7.x to 8.5.2."
See Technote 7022205 for Web Conference and Dial-in Information
The next day on August 17th, 2011 at 11:00 AM EDT the topic will be "Upgrading IBM Sametime Clients: 7.x to 8.5.2."
See Technote 7022206 for Web Conference and Dial-in information
Support for Sametime 7.0.x and Sametime 7.5.x ends on September 30, 2011 so now is an excellent time to be planning your upgrade to Sametime 8.5.2.
Check the Lotus Software lifecycle dates page for maintenance and support dates for any product.