If you are using an iPad, iPhone or iPod with iOS 4 or are supporting an Exchange environment with users using those devices, then you might have been experiencing slow performance or sync not working at all. The same is true when using a 3rd party solution which also uses an ActiveSync implementation such as Google Apps.
The Exchange Team has released an overview of the issues that you can encounter and the needed fixes or the current status of (Apple) getting a fix out.
