I complet my registration for CPT in July 2017, Now I want to apply for December exam. Is my study material appropriate for December exam?
May be u fail in Dec thats y u want to reattempt.
There is no change in Study Material As of Now.
For More Details on Orientation and IT Training.
U need to visit http://www.icai.org.in.
Thanks,
Azim

Yes, you can go with the july 2017 study material that you have as it is based on the changes that were implemented by ICAI and from that time till now there has been no major changes and the syllabus is the same.
Hope it helps.
Good Luck!