In addition to 39 new classes, 7 classes have been renamed. Through a #define statement, some of the old names remain compatible with ATL 2.1. However, it is recommended that you use the new names. For more information, see Obsolete ATL Topics.
| Old name | New name |
| CcomConnectionPoint | IConnectionPointImpl (Not backward compatible. You must use the new name.) |
| CcomConnectionPointContainerImpl | IConnectionPointContainerImpl |
| CcomDualImpl | IDispatchImpl |
| CcomDynamicArrayCONNECTDATA | CComDynamicUnkArray (Not backward compatible. You must use the new name.) |
| CcomISupportErrorInfoImpl | ISupportErrorInfoImpl |
| CcomProvideClassInfo2Impl | IProvideClassInfo2Impl |
| CcomStaticArrayCONNECTDATA | CComUnkArray (Not backward compatible. You must use the new name.) |