As any iPhone enthusiast knows, IOS4 has been released. Unfortunately there have been a large number of reports of issues surrounding IOS4’s implementation of ActiveSync.
Issues reported include dramatic increases in resource usage on Exchange servers (causing potentially severe issues), issues with iPhone sending and receiving mail, and issues with iPhones not syncing correctly with regards to their mail and calendar items.
Apple has released a single update, but it only addresses one of the seemingly many issues. My company, Azaleos, is currently taking the stance of advising customers to hold off on upgrading until Apple and Microsoft work out these issues.