2026 marks the seventh birthday of OSE. In that time, we’ve seen the game grow from a niche online project to one of the most beloved old-school RPGs. Hundreds of adventures and supplements have been published for OSE, including around 20 official publications from Necrotic Gnome. And that’s just the beginning. We have big plans for OSE going forward, so read on to see what’s in store!

Core Rules Consolidation

OSE has always been available in multiple formats — as of 2025, we publish the Classic Fantasy Rules Tome, the Advanced Fantasy Player’s and Referee’s Tomes, the Classic Game Set, and the Advanced Expansion Set. That’s a total of 5 core rules products, across two different “flavours” (Classic versus Advanced Fantasy) and two different formats (books versus box sets).

While publishing the game in these multiple formats caters to different tastes and preferences, it's also proven to be confusing for new players, not to mention logistically complicated keeping all the different formats in stock. Going forward, we’ll be consolidating Old-School Essentials into a pair of core books: the OSE Player’s Book and Referee’s Book. These two books form what we’re calling the 2026 Update of OSE.

OSE 2026 Update

These two 256-page hardcovers will be the definitive OSE core books. As you can probably deduce from the covers (now redesigned to spotlight Peter Mullen's fantastic art!), the 2026 Update books are equivalent to the current Advanced Fantasy Player’s and Referee’s Tomes. These are the most popular of the currently available formats of OSE, so we decided to carry them forward as the definitive version of the game.

What’s New?

Apart from the new cover design and expanded cover art, there are a few noteworthy changes inside the 2026 Update books:

• New art. Around 200 new illustrations, including an illustration for every class and race, lots more monsters, and a set of beautiful colour paintings by Jacob Fleming.
  
• Introductory material and examples. A completely rewritten introduction plus dozens of new examples of rules and gameplay, including fully detailed examples of creating a wilderness region, base town, and dungeon.
  
• Glossary and index. The Player’s Book now contains a glossary of common game terms and a full index of rules topics.
  
• Basic play appendices. An appendix in each book notes which content is derived from the Basic/Expert D&D rules and provides additional tables for those seeking a core B/X experience.
  
• New optional rules. We're adding a handful of extra optional rules, including training, XP for magic items, hovering at death’s door, and higher Hit Die types (à la AD&D).
  
• Class tweaks. Minor tweaks to the assassin, barbarian, knight, and ranger classes, based on feedback from players over the past 6 years. (As mentioned in our end-of-2024 update.)
  
• Minor rules fixes. A small number of tiny fixes to core rules for the sake of B/X fidelity, for example attacking from behind, sea-based encounter chances, and travel effects of roads and trails.

We've integrated years of feedback from fans to create these beautifully honed core rule books and can’t wait to see them on gaming tables!

100% Compatible With Older Books

If you have older OSE rule books or box sets, please continue to enjoy them! The 2026 Update is 100% compatible with older products. All of the changes noted above—aside from the minor class tweaks and tiny rules fixes—introduce additional or optional material, none of which supersedes anything in existing books. You’ll be able to play OSE at the same table as someone using the 2026 Update books without issue. 

What’s more, once the 2026 Update books are out, we will publish a free PDF containing the small number of optional rules additions and minor tweaks for players with existing books to use in their games.

100% OGL-Free

You may recall the controversy in 2023 around Wizards of the Coast’s attempt to revoke the Open Game License upon which many old-school RPGs are based. In response to that legal peril, we’ve completely re-edited OSE’s text to be able to publish the game outside of the Open Game License. This has no effect on the rules of the game, but makes OSE more resilient to any potential future wrangling by WOTC’s lawyers.

Timeline

We don’t have a final release date for the 2026 Update books just yet, but keep an eye on our newsletter for updates!

More Dungeons! More Demons! More OSE!

In addition to the 2026 Update rule books, we have big plans for OSE in 2026 and beyond. With our expanded development team, we have more adventures and more issues of the Carcass Crawler zine in the works for 2026, alongside the Dungeons of the Undermoon Starter Set (featuring a full adventure, base town, and campaign starting region) and our hotly anticipated Demonic Grimoire supplement (clocking in at 176 pages of fiendish goodness)—both to be published in 2026.

It's an exciting time for Old-School Essentials, and we can't wait to get all this new material into your hands!