Liz Schuh, Head of Publishing and Licensing for Dungeons & Dragons, described the policy in an interview with ICv2 in August (see "Exclusive Interview on 'D&D: The Sundering,' Part 2").
"We really wanted to make sure that all D&D players could engage with this great adventure story and so we know that some people are playing with the playtest rules, some are diehard 4th Edition players, and we also wanted to open it up to people who may still be using 3.5 rules. We think it really expands out the audience and lets all D&D players enjoy the fun.
"A big part of this is shifting our emphasis away from the rules we’re delivering to the great stories that we’re delivering. This is a great Sundering adventure; it lets people participate in the future of the Forgotten Realms; and for us, whatever rule set is their favorite rule set, that’s great and we don’t want to get in the way of that decision. We want them to participate in this great story.
"A big part of this is shifting our emphasis away from the rules we’re delivering to the great stories that we’re delivering. This is a great Sundering adventure; it lets people participate in the future of the Forgotten Realms; and for us, whatever rule set is their favorite rule set, that’s great and we don’t want to get in the way of that decision. We want them to participate in this great story.
We asked WotC for an explanation of the apparent conflict between the two statements, and were told that the new adventure is playable with any version of the rules, but that WotC is now "encouraging" the use of D&D Next rules for D&D Encounters. Here’s the explanation from a Wizards of the Coast spokesperson, in full:
"The Scourge of the Sword Coast Adventure, which will be available for download at dndclassics.com, can be played with whichever edition of D&D you prefer. This is in-line with our strategy to put the emphasis on the story and allow players to choose the rules they use to experience that story. We made the decision to extract the rules from the body of the product, leaving just the narrative elements, and we offered the stat blocks separate from the product. That still remains the case.
"The Encounters program has always been about providing a great in-store play experience, and the support materials that Wizards provides to participating Wizards Play Network locations is with that goal in mind. We encouraged stores to run the first two Sundering adventures in 4th Edition or D&D Next, however the in-store entertainment experience is truly up to the store owners. For 2014, we are encouraging stores to focus on running the adventures using D&D Next.
"The Encounters program has always been about providing a great in-store play experience, and the support materials that Wizards provides to participating Wizards Play Network locations is with that goal in mind. We encouraged stores to run the first two Sundering adventures in 4th Edition or D&D Next, however the in-store entertainment experience is truly up to the store owners. For 2014, we are encouraging stores to focus on running the adventures using D&D Next.
This change to emphasize the use of the D&D Next rule set for Encounters is undoubtedly to prepare the ground for the official launch of the new edition of the game, announced today for Summer 2014 (see "'D&D Next' Launch Date Set").