Will Chinese travel document which was issued on April 2014 still be useful on 2015?

Dear Sir/Mam,
My son has a Chinese travel document which was issued on April 2014. I was notified that this document could last 2 years. But since the new Chinese travel document policy was released on May 2015, will my son's previous issued Chinese travel document still be useful this year? Thank you.
Yours,
Sincerely,
Jessie He