The CBK has not been updated but, I would say that there is a lot of good information that is still relevant to the CSSLP. I would also encourage you to download the Exam Outline as that is a good reference for self-study. In addition to the Exam Outline, we also have a CBK reference list that would be helpful with self-studyhttps://www.isc2.org/Certifications/References. We also have flash cards available for an additional self-study resource.
If you have any additional questions regarding the current CSSLP Online Instructor-Led course or any of the resources provided, please do not hesitate to contact me directly and I will provide the assistance needed.