Bumping this, with my own observations to add to mapcat's.
Construction of the Arnprior bypass is complete. While there has been talk of extending ON 417 again west toward Renfrew, there is no new construction in progress, so this isn't a moving target.
The highway has been twinned west of new exit 187, to just west of the Schell Dr. underpass/closed intersection (detour signage west of there indicate there had been an intersection, but not anymore). Eastbound, the 100km/h limit reserved for 400-series freeways starts just west of Schell Dr., but the first ON 417 sign is just east of new exit 187. Westbound, there is an ON 417 sign just west of exit 187. The first ON 17 marker WB, and the last such marker EB, are both west of Schell Dr. There is no signage explicitly saying where ON 17 ends and ON 417 begins.
We could do what we did last time, and move the ON 17/ON 417 junction to new exit 187. Or we could put the junction west of exit 187 at Schell Rd., which is more consistent with Mapnik and Google Maps. I'm OK with either, but let's do one or the other.