China’s visa rules change often and sometimes unpredictably.
Recently a new policy has been introduced which requires visa applicants applying on passports issued from January 2015 onwards to show their old passport at the time of application for a visa. This applies regardless of whether you had any Chinese visas in your old passport.
In some points of application, a picture of the personal information page in your old passport will be sufficient, but in others you may need the physical passport. Please report your experiences in the comments section below to help others. Thanks!