By request from a couple customers we've added two variants of existing APIs. tmEnterThread/tmLeaveThread let you manually specify your thread IDs, thus giving support for logical threads. This is handy if you have a single thread for something like AI but you want to visualize different subtasks/coroutines/fibers individually.
The other API addition is the ability to pass a specific time value to tmBeginTimeSpan and tmEndTimeSpan via the tmBegin/EndTimeSpanAt variants. Now you can measure an event indirectly, such as a GPU fence, and see it on the timeline.