"New rulebook" refers to a fresh set of rules or guidelines that have been created or implemented. It suggests that there have been changes in the way things are done, and a new framework or standard is now in place. Full definition
Heck, he might just change his mind and write a whole new rulebook at the last minute, maybe call it the New Testament, and then only people who are left handed are allowed in heaven. (religion.blogs.cnn.com)
Writing a brand new rulebook post-Paris began with a fair amount of head - scratching. (climatenetwork.org)
Those of you thinking about industry careers, on the other hand, will need to learn a whole new rulebook. (sciencemag.org)