Is the current Canada/Central zoneinfo correct?

I am the guy who maintains the zoneinfo stuff in Solaris 2 and one of our customers just submitted a bug against the current Canada/Central (aka America/Winnepeg) entry complaining that it switches back to Standard Time one week too early. The current entry for Canada/Central says that it should switch on the last Sunday in September, which would have been yesterday, the 24th. Who is right? Our customer or the current zoneinfo source? alan perry