diff --git a/patches/400952.patch b/patches/400952.patch
new file mode 100644
index 00000000..7eefa4ac
--- /dev/null
+++ b/patches/400952.patch
@@ -0,0 +1,260 @@
+diff --git a/pkgs/by-name/ma/matrix-appservice-slack/package.json b/pkgs/by-name/ma/matrix-appservice-slack/package.json
+deleted file mode 100644
+index d4a27436aea1ea..00000000000000
+--- a/pkgs/by-name/ma/matrix-appservice-slack/package.json
++++ /dev/null
+@@ -1,96 +0,0 @@
+-{
+-  "name": "matrix-appservice-slack",
+-  "version": "2.1.2",
+-  "description": "A Matrix <--> Slack bridge",
+-  "engines": {
+-    "node": ">=16 <=18"
+-  },
+-  "main": "app.js",
+-  "scripts": {
+-    "prepare": "yarn build",
+-    "start": "node ./lib/app.js",
+-    "build": "yarn build:app && yarn build:widget",
+-    "build:app": "tsc --build",
+-    "build:widget": "vite build --config widget/vite.config.ts",
+-    "test": "yarn test:unit && yarn test:integration",
+-    "test:unit": "mocha --require ts-node/register --recursive tests/unit/*.ts",
+-    "test:integration": "mocha --exit --reporter list --ui bdd --require ts-node/register --recursive tests/integration/*.ts",
+-    "test:postgres": "SLACKBRIDGE_TEST_ENABLEPG=yes mocha --reporter list --ui bdd --require ts-node/register --recursive tests/integration/PgDatastoreTest.ts",
+-    "lint": "eslint -c .eslintrc.js ./src && eslint -c ./widget/.eslintrc.js 'widget/src/**/*.{ts,tsx}'"
+-  },
+-  "repository": {
+-    "type": "git",
+-    "url": "git+https://github.com/matrix-org/matrix-appservice-slack.git"
+-  },
+-  "keywords": [
+-    "matrix-org",
+-    "slack"
+-  ],
+-  "author": "Matrix.org",
+-  "license": "Apache-2.0",
+-  "bugs": {
+-    "url": "https://github.com/matrix-org/matrix-appservice-slack/issues"
+-  },
+-  "homepage": "https://github.com/matrix-org/matrix-appservice-slack#readme",
+-  "dependencies": {
+-    "@alloc/quick-lru": "^5.2.0",
+-    "@slack/logger": "^3.0.0",
+-    "@slack/rtm-api": "^6.0.0",
+-    "@slack/web-api": "^6.7.2",
+-    "Slackdown": "git+https://Half-Shot@github.com/half-shot/slackdown.git",
+-    "ajv": "^8.12.0",
+-    "axios": "^0.27.2",
+-    "classnames": "^2.3.2",
+-    "escape-string-regexp": "^4.0.0",
+-    "https-proxy-agent": "^5.0.1",
+-    "matrix-appservice-bridge": "^8.1.2",
+-    "matrix-widget-api": "^1.1.1",
+-    "minimist": "^1.2.6",
+-    "nedb": "^1.8.0",
+-    "node-emoji": "^1.10.0",
+-    "nunjucks": "^3.2.4",
+-    "p-queue": "^6.0.0",
+-    "pg-promise": "^10.11.1",
+-    "randomstring": "^1.2.1",
+-    "react": "^18.2.0",
+-    "react-dom": "^18.2.0",
+-    "url-join": "^5.0.0",
+-    "uuid": "^8.3.2",
+-    "yargs": "17.5.1"
+-  },
+-  "devDependencies": {
+-    "@tailwindcss/forms": "^0.5.3",
+-    "@tsconfig/node16": "^1.0.3",
+-    "@types/chai": "^4.2.21",
+-    "@types/js-yaml": "^4.0.2",
+-    "@types/mocha": "^9.1.1",
+-    "@types/nedb": "^1.8.12",
+-    "@types/node": "^18.6.1",
+-    "@types/node-emoji": "^1.8.1",
+-    "@types/nunjucks": "^3.1.5",
+-    "@types/randomstring": "^1.1.7",
+-    "@types/react": "^18.0.27",
+-    "@types/react-dom": "^18.0.10",
+-    "@types/uuid": "^8.3.1",
+-    "@types/yargs": "17.0.10",
+-    "@typescript-eslint/eslint-plugin": "^5.0.0",
+-    "@typescript-eslint/parser": "^5.50.0",
+-    "@vitejs/plugin-react": "^3.1.0",
+-    "autoprefixer": "^10.4.13",
+-    "chai": "^4.3.4",
+-    "eslint": "^8.20.0",
+-    "eslint-plugin-jsdoc": "^39.3.3",
+-    "eslint-plugin-prefer-arrow": "^1.2.3",
+-    "eslint-plugin-react": "^7.32.2",
+-    "eslint-plugin-react-hooks": "^4.6.0",
+-    "js-yaml": "^4.1.0",
+-    "mocha": "^10.0.0",
+-    "postcss": "^8.4.21",
+-    "prom-client": "^14.0.1",
+-    "source-map-support": "^0.5.19",
+-    "tailwindcss": "^3.2.4",
+-    "ts-node": "^10.1.0",
+-    "typescript": "^4.4.3",
+-    "vite": "^4.1.1"
+-  }
+-}
+diff --git a/pkgs/by-name/ma/matrix-appservice-slack/package.nix b/pkgs/by-name/ma/matrix-appservice-slack/package.nix
+index b37ebccbf2f275..480bd57ba3c8bb 100644
+--- a/pkgs/by-name/ma/matrix-appservice-slack/package.nix
++++ b/pkgs/by-name/ma/matrix-appservice-slack/package.nix
+@@ -1,55 +1,74 @@
+ {
+   lib,
++  stdenv,
+   fetchFromGitHub,
+   fetchYarnDeps,
++  yarnConfigHook,
++  yarnBuildHook,
++  nodejs_20,
+   makeWrapper,
+-  mkYarnPackage,
+-  nodejs_18,
+   callPackage,
+ }:
+ 
+ let
+-  data = lib.importJSON ./pin.json;
+-  nodejs = nodejs_18;
++  nodejs = nodejs_20;
+   matrix-sdk-crypto-nodejs = callPackage ./matrix-sdk-crypto-nodejs-0_1_0-beta_3/package.nix { };
+ in
+-mkYarnPackage rec {
+-  inherit nodejs;
+-
++stdenv.mkDerivation rec {
+   pname = "matrix-appservice-slack";
+-  version = data.version;
++  version = "2.1.2";
+ 
+-  packageJSON = ./package.json;
+   src = fetchFromGitHub {
+     owner = "matrix-org";
+     repo = "matrix-appservice-slack";
+-    rev = data.version;
+-    hash = data.srcHash;
++    rev = version;
++    hash = "sha256-e9k+5xvgHkVt/fKAr0XhYjbEzHYwdGRdqiPWWbT0T5M=";
+   };
+ 
+-  offlineCache = fetchYarnDeps {
++  nativeBuildInputs = [
++    makeWrapper
++    nodejs
++    yarnConfigHook
++    yarnBuildHook
++  ];
++
++  postPatch = ''
++    # upstream locks the supported node version range down, which we don't want
++    substituteInPlace package.json \
++      --replace-fail '"node": ">=16 <=18"' '"node": ">=16"'
++  '';
++
++  yarnOfflineCache = fetchYarnDeps {
+     yarnLock = src + "/yarn.lock";
+-    sha256 = data.yarnHash;
+-  };
+-  packageResolutions = {
+-    "@matrix-org/matrix-sdk-crypto-nodejs" =
+-      "${matrix-sdk-crypto-nodejs}/lib/node_modules/@matrix-org/matrix-sdk-crypto-nodejs";
++    hash = "sha256-fw4gXh4wfzHFgUYiEAvbhVrjno/E70iMhdk60F3Oxgg=";
+   };
+ 
+-  nativeBuildInputs = [ makeWrapper ];
++  preBuild = ''
++    # matrix-sdk-crypto-nodejs needs rust to be built from source, which we can achieve in a separate derivation
+ 
+-  buildPhase = ''
+-    runHook preBuild
+-    yarn run build
+-    runHook postBuild
++    # first, we ensure the separately built module's version is actually the same as the version in the lockfile
++    diff ${matrix-sdk-crypto-nodejs}/lib/node_modules/@matrix-org/matrix-sdk-crypto-nodejs/package.json node_modules/@matrix-org/matrix-sdk-crypto-nodejs/package.json
++
++    # then we copy it into node_modules
++    rm -r node_modules/@matrix-org/matrix-sdk-crypto-nodejs
++    ln -s ${matrix-sdk-crypto-nodejs}/lib/node_modules/@matrix-org/matrix-sdk-crypto-nodejs node_modules/@matrix-org/matrix-sdk-crypto-nodejs
+   '';
+ 
+-  postInstall = ''
+-    makeWrapper '${nodejs}/bin/node' "$out/bin/matrix-appservice-slack" --add-flags \
+-        "$out/libexec/matrix-appservice-slack/deps/matrix-appservice-slack/lib/app.js"
++  installPhase = ''
++    runHook preInstall
++
++    mkdir -p "$out"/libexec/matrix-appservice-slack
++    cp -r package.json lib node_modules "$out"/libexec/matrix-appservice-slack
++
++    makeWrapper '${lib.getExe nodejs}' "$out/bin/matrix-appservice-slack" --add-flags \
++        "$out/libexec/matrix-appservice-slack/lib/app.js"
++
++    runHook postInstall
+   '';
+ 
+-  doDist = false;
++  passthru = {
++    inherit matrix-sdk-crypto-nodejs;
++  };
+ 
+   meta = with lib; {
+     description = "Matrix <--> Slack bridge";
+diff --git a/pkgs/by-name/ma/matrix-appservice-slack/pin.json b/pkgs/by-name/ma/matrix-appservice-slack/pin.json
+deleted file mode 100644
+index 3adfcbabae62b4..00000000000000
+--- a/pkgs/by-name/ma/matrix-appservice-slack/pin.json
++++ /dev/null
+@@ -1,5 +0,0 @@
+-{
+-  "version": "2.1.2",
+-  "srcHash": "sha256-e9k+5xvgHkVt/fKAr0XhYjbEzHYwdGRdqiPWWbT0T5M=",
+-  "yarnHash": "0266rrfx0fnrhn64ivy4iygf6nl5vc5i08j6h72k2zrh3rg203kz"
+-}
+diff --git a/pkgs/by-name/ma/matrix-appservice-slack/update.sh b/pkgs/by-name/ma/matrix-appservice-slack/update.sh
+deleted file mode 100755
+index dc3bab3311f21c..00000000000000
+--- a/pkgs/by-name/ma/matrix-appservice-slack/update.sh
++++ /dev/null
+@@ -1,36 +0,0 @@
+-#!/usr/bin/env nix-shell
+-#!nix-shell -I nixpkgs=../../../../ -i bash -p nix curl jq prefetch-yarn-deps nix-prefetch-github nix-prefetch-git
+-
+-if [ "$#" -gt 1 ] || [[ "$1" == -* ]]; then
+-  echo "Regenerates packaging data for matrix-appservice-slack."
+-  echo "Usage: $0 [git release tag]"
+-  exit 1
+-fi
+-
+-version="$1"
+-
+-set -euo pipefail
+-
+-if [ -z "$version" ]; then
+-  version="$(curl "https://api.github.com/repos/matrix-org/matrix-appservice-slack/releases?per_page=1" | jq -r '.[0].tag_name')"
+-fi
+-
+-src="https://raw.githubusercontent.com/matrix-org/matrix-appservice-slack/$version"
+-src_hash=$(nix-prefetch-github matrix-org matrix-appservice-slack --rev ${version} | jq -r .hash)
+-
+-tmpdir=$(mktemp -d)
+-trap 'rm -rf "$tmpdir"' EXIT
+-
+-pushd $tmpdir
+-curl -O "$src/yarn.lock"
+-yarn_hash=$(prefetch-yarn-deps yarn.lock)
+-popd
+-
+-curl -O "$src/package.json"
+-cat > pin.json << EOF
+-{
+-  "version": "$version",
+-  "srcHash": "$src_hash",
+-  "yarnHash": "$yarn_hash"
+-}
+-EOF