# Slay the Spire 2 Major Update #2 - v0.107.1

- Product: Slay the Spire 2 (https://whatsnew.fyi/product/slay-the-spire-2)
- Vendor: Mega Crit
- Date: 2026-06-19
- Original notes: https://store.steampowered.com/news/app/2868840/view/710026912607505280
- Permalink: https://whatsnew.fyi/product/slay-the-spire-2/releases/2026-06-19-major-update-2-v0.107.1

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **fixed** — Fixed unusual RNG correlation problems where results from different pseudo-random number generators were predictable and correlated
- **changed** — Replaced PRNG implementation with xoshiro256** for improved randomness distribution
- **added** — Added Steam Workshop support for browsing and installing mods directly from the workshop
- **added** — Added the Bestiary as a new final screen in the Compendium displaying encountered monsters, their moves, and animations
- **removed** — Removed The Doormaker boss from the game
- **added** — Added Aeonglass as a new Act 3 boss
- **changed** — Totally reworked Hive's Infested Prism enemy
- **added** — Added Damage Leader badge for dealing the most damage to enemies in multiplayer
- **added** — Added Debuffer badge for applying the most debuffs in multiplayer
- **added** — Added C-c-c-Combo badge for playing 20 cards in a single turn
- **changed** — Terminal run modifier can no longer bring a player below 1 HP

Hey Slayers, our second major main branch update is here with 4 patches in 1 (not including hotfixes)! While we'll be covering a lot of things that beta players will already be used to, there are also a few big changes that will be totally new for everyone. One of those has been highly requested by the community in the past few days and another has been _very_ highly requested by the community in the past few months, so let's get into it!

##### RNG Rework

Ed here, one of the Mega Crit engineers. It turns out that everyone complaining about receiving Debt too often from Neow's Bones was right! We did, in fact, have some unusual RNG problems.

Huge shoutout to **tckmn** for doing the research - their [eight-hour descent into madness](https://www.twitch.tv/videos/2794202198) was an entertaining watch, and we wouldn't have caught the issue without it. If you're interested in the nitty-gritty, read [tckmn's full writeup](https://tck.mn/blog/correlated-randomness-sts2/). Here is a short version.

Most games, including STS2, use [pseudo-random number generators](https://en.wikipedia.org/wiki/Pseudorandom_number_generator) (PRNGs). A PRNG is fed a seed value, and given the same seed value, a PRNG will always generate the same sequence of random numbers.

Each run has one primary “run seed”, a sequence of twelve numbers and letters. However, a run actually contains multiple PRNGs that individually influence your deck draw, your combat rewards, your event choices, and the rest of the random elements in the run. Each one uses a seed derived from the run seed.

Since we fed different seeds to each PRNG, we expected their results to be completely unrelated. But we were wrong, and it turns out that our strategy allowed players to predict outcomes given knowledge of unrelated parts of the game.

Let’s visualize one example: the correlation between your first act and the curse you receive from Neow’s Bones. In both cases, we generate a decimal between 0 and 1, but from different PRNGs.

 - For your first act, if the decimal generated is less than 0.5, you get Overgrowth; otherwise, you get Underdocks.
 - For Neow's Bones’ curse, we use the decimal to pick from a list of ten curses. Between 0 and 0.1 you get Clumsy, between 0.1 and 0.2 you get Debt, and so on.

Here is a scatterplot of the raw numbers generated given 10000 random run seeds on v0.103.3:

There is clear correlation in this result. For example, if our act roll is >0.5 (we’re in the Underdocks), then it’s highly likely that our Neow’s Bones curse roll will be <0.5, which cuts the potential curses you can obtain in half.

Aside from the balance ramifications: once knowledge of this exploit is out there, players are naturally incentivized to use it to play optimally. We don’t want to encourage rote memorization of correlation tables, as it is tedious and unfun.

Thus, in v0.107.1, we replaced our PRNG implementation with a more modern one ([xoshiro256**](https://prng.di.unimi.it/)). The resulting scatterplot is evenly distributed, exhibiting no human-detectable correlation.

Rest assured that your suffering is now truly random!

Speaking of updates that will be new to all players, I’ve also been busy working on support for…

##### Steam Workshop

We built STS2 with modding in mind, and the game has had an integrated mod loader from day one. It's been awesome seeing the outpouring of creativity from the community! But we purposefully haven't been advertising mod support, as we knew it still needed some work.

Previously, the only supported way to install mods was to download them and place them next to the executable. With this patch, **Steam Workshop support has officially been added!** Now, you can browse and install mods directly from the workshop, and they will be automatically downloaded to all devices where you play on Steam.

If you are a mod creator, upload your mods using the tool (https://github.com/megacrit/sts2-mod-uploader).

And if you're interested in playing some mo

_[Truncated at 4000 characters — full notes: https://store.steampowered.com/news/app/2868840/view/710026912607505280]_