There's a good thread in the AC forum posted by Andrew Liu, an AC insider, which has the current status of the refurbishment. It's titled something like "XM Update".
All domestic/Nth American internal fleet is done bar a couple of examples. The International fleet is done except for A330's (see below) & 3 763's they are not going to do. These examples will be placed on domestic and international "leisure" routes like Carribbean, Dublin etc.
The last examples of their international fleet to undergo the process are the A330's, the first of which is now in the shop getting done. They only have 8 of them to do, so once the first one is done and gets certified by the Canadian authorities, then the rest should follow.
AC's booking pages on their website shows which routes/flights are guaranteed a new cabin aircraft if you need to check a certain flight/route.