It appears that NZ and Malaysia negotiated exceptions that will delay the new laws, so there will be no new public domain material for many years, but old material will not be affected. It also appears that Canada failed to negotiate such an exception, so public domain material from the past 20 years would revert.

http://www.michaelgeist.ca/2015/10/canada-caves-on-copyright...

http://beehive.govt.nz/sites/all/files/TPP-Q&A-Oct-2015.pdf