I have exchange 2003 sp2 running (server 2003r2) and only issue I have is android phones cannot send attachments. looking at the logs (using nitrodesk touchdown for android) I see an error 413 , “413 request entity too large” for any failed message.
no attachment and messages are fine, even html. issue is only when attachment added. I have not yet seen if there is a limit that does send but I know ~50 KB fails.