The last time I went to a Scotiabank ATM, I got five fresh $20s with prefix FZK. So it appears that, in my province, the FZ* prefixes are now starting to appear, but I expect to probably see some prefixes jumped over down the road. The Lane-Macklem prefixes are experiencing a slower release, with only FZT, FZV, FZZ and FLA released to date (albeit in smaller quantities).
I am thinking the oldest of the existing Polymer $20s are finally starting to get replaced in my neck of the woods as of lately.