I have several hundred clients using various Outlook and Outlook Express versions around the world connecting to my email server. These clientss are all setup to use SSL encryption to connect to my server. I am in the process of migrating off of my old Communigate Pro email server and moving to Exchange 2010 and it is my understanding that some of my older Outlook and Outlook Express clients may not connect to Exchange 2010 when using Outlook's SSL settings. SSL settings are very important because we want to make sure none of our email clients are sending in clear text.
I'm looking for some articles that discuss which Outlook / Outlook Express clients do and do not work with Exchange 2010 SSL. I need to advise my email users on what version of Outlook / Outlook Express they need to obtain. All of the clients use IMAP and POP3. I'm guessing several users are using Outlook 2003, 2002, and few still may have Outlook 2000. Several may still be using Outlook Express 5.0 & 6.0.
Thanks for any help you can give!