Max Age
Cant answer your question directly but my Zambian Experience from 2008might indicate.
As a Single Engine Commercial Pilot (not ATLP), once I reached the age of 60 I could only continue to fly to age 65 if I had a co pilot less than 60 years of age. This was obviously not practical in the bush pilot enviroment of C206/C210. But quite a few operators (maybe most now) fly the C208 Caravan as a two crew operation, so there is a window there.
If your are twin rated the possibilities would be much higher but depend on the size of the Operator and his crew roster.
Good Luck.