We transition the handbook from the current (final) release to the new upcoming release (the version that would be in testing snapshot form and later in beta then RC) almost immediately after the handbook wiki is published in its various forms (for the 'current' release).
There are only about four consistently active editors on the wiki. The wiki is open to anyone to assist with any editing tasks, including those that do not involve English language proficiency. As of today, there are over 400 different external links within the handbook, over 100 separate handbook wiki pages, 11 primary chapters, 95 sub-chapter pages (15 of these for different desktop information, and 19 for the different control panel items). The handbook continues to grow along with the capabilities of PC-BSD. This is not a complaint about too much work for too few people, but consider that due to the vastness of the handbook in relation to the numbers of editors it will certainly take longer to accomplish and sometimes things can get overlooked.
It is easy to assist: create an account on the wiki, verify your email address, login and start editing. Ask questions along the way but do not fear your mistakes because they will become known and can be corrected as necessary. It is very much a cooperative community effort, no one is excluded (except link spammers and those who intentionally vandalize).