Synchronous reading using ReadAny with AsyncMode or ReadSynchronous is replaced with a Read method and AsyncMode no longer exists. Asynchronous reading is now done with the BeginRead method. This was chosen to follow the .NET patterns closer.
Subscription callback signatures have changed. The new version now includes more information than just the value returned, such as the PLC address. This allows multiple subscriptions to use the same call back. A new component called DataSubscriber will make subscriptions a breeze. Simply add the component to the form, double click and you will be taken to a callback routine where you can write the code to process the value.
A lot of attention has been given to the ControlLogix driver to make it more stable and faster. It is now using a background thread to process subscription updates and throttles the messages sent to the PLC. This should eliminate the ignored requests which causes the "No Response -20" error.