Successive volumes are planned for subsequent years. THis provision makes allowances for "adjustments" in rules with the passing of time. -- steve2
In my ongoing study of English literature and grammar, I find a curious connection between "retcon" and WT modus operandi:
There are various motivations for applying retroactive continuity. The changes may occur to accommodate sequels or derivative works, allowing newer authors or creators to revise the diegetic (in-story) history to include a course of events that would not have been possible in the story's original continuity. Retcons allow for authors to reintroduce popular characters and resolve errors in chronology. Another form of retroactive continuity involves placing well-known characters in a parallel universe. This approach can be used to allow familiar elements of a story to be explored in an entirely new context, without affecting external elements. Additionally, this approach can be used to retcon former events in a franchise timeline.