diff --git a/.eslintignore b/.eslintignore
index 6f9a60d7..8f9e81e0 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,3 +1,17 @@
 lib/
 node_modules/
 .eslintrc.js
+
+# pre-commit run --all-files
+*.conf
+Dockerfile
+*.gif
+*.json
+LICENSE
+*.lock
+*.md
+NOTICE
+*.py
+*.sh
+*.yaml
+*.yml
diff --git a/.github/workflows/mjolnir.yml b/.github/workflows/mjolnir.yml
index f5cc4eff..b2a23bee 100644
--- a/.github/workflows/mjolnir.yml
+++ b/.github/workflows/mjolnir.yml
@@ -21,9 +21,10 @@ jobs:
       uses: actions/setup-node@v4
       with:
         node-version: '18'
-    - run: yarn install
-    - run: yarn build
-    - run: yarn lint
+    - run: corepack enable
+    - run: corepack yarn install
+    - run: corepack yarn build
+    - run: corepack yarn lint
   unit:
     name: Unit tests
     runs-on: ubuntu-latest
@@ -33,8 +34,8 @@ jobs:
       uses: actions/setup-node@v4
       with:
         node-version: '18'
-    - run: yarn install
-    - run: yarn test
+    - run: corepack yarn install
+    - run: corepack yarn test
   integration:
     name: Integration tests
     runs-on: ubuntu-latest
@@ -52,7 +53,7 @@ jobs:
     - name: Setup image
       run: RUST_LOG=debug,hyper=info,rusttls=info mx-tester build up
     - name: Setup dependencies
-      run: yarn install
+      run: corepack yarn install
     - name: Run tests
       run: RUST_LOG=debug,hyper=info,rusttls=info mx-tester run
     - name: Cleanup
@@ -74,8 +75,8 @@ jobs:
     - name: Setup image
       run: RUST_LOG=debug,hyper=info,rusttls=info mx-tester build up
     - name: Setup dependencies
-      run: yarn install
+      run: corepack yarn install
     - name: Run tests
-      run: yarn test:appservice:integration
+      run: corepack yarn test:appservice:integration
     - name: Cleanup
       run: mx-tester down
diff --git a/.gitignore b/.gitignore
index 40afcedc..dc2c0c24 100644
--- a/.gitignore
+++ b/.gitignore
@@ -77,3 +77,8 @@ mjolnir.egg-info/
 
 # VS
 .vs
+
+# Yarn versions through corepack
+.yarn
+# Only contains possibly broken path, replaced by .yarnrc.yml in modern Yarn
+.yarnrc
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 8a6cd815..d35b0123 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -23,5 +23,5 @@ repos:
     hooks:
       - id: yarn-lint
         name: linter
-        entry: yarn lint --cache
+        entry: corepack yarn lint --cache --quiet
         language: system
diff --git a/mx-tester.yml b/mx-tester.yml
index 12e9e5b8..427b6e40 100644
--- a/mx-tester.yml
+++ b/mx-tester.yml
@@ -7,8 +7,8 @@ up:
     - until psql postgres://mjolnir-tester:mjolnir-test@127.0.0.1:8083/mjolnir-test-db -c ""; do echo "Waiting for psql..."; sleep 1s; done
     # Launch the reverse proxy, listening for connections *only* on the local host.
     - docker run --rm --network host --name mjolnir-test-reverse-proxy -p 127.0.0.1:8081:80 -v $MX_TEST_CWD/test/nginx.conf:/etc/nginx/nginx.conf:ro -d nginx
-    - yarn install
-    - npx ts-node src/appservice/cli.ts -r -u "http://host.docker.internal:9000"
+    - corepack yarn install
+    - corepack npx ts-node src/appservice/cli.ts -r -u "http://host.docker.internal:9000"
     - cp mjolnir-registration.yaml $MX_TEST_SYNAPSE_DIR/data/
   after:
     # Wait until Synapse is ready
@@ -16,7 +16,7 @@ up:
     - echo "Synapse is ready"
 
 run:
-  - yarn test:integration
+  - corepack yarn test:integration
 
 down:
   finally:
diff --git a/package.json b/package.json
index 52b80ca0..236a6638 100644
--- a/package.json
+++ b/package.json
@@ -9,16 +9,16 @@
   "private": true,
   "scripts": {
     "build": "tsc --project test/tsconfig.json && tsc > /dev/null 2>&1",
-    "postbuild": "yarn describe-version",
+    "postbuild": "corepack yarn describe-version",
     "describe-version": "(git describe > version.txt.tmp && mv version.txt.tmp version.txt) || true && rm -f version.txt.tmp",
     "remove-tests-from-lib": "rm -rf lib/test/ && cp -r lib/src/* lib/ && rm -rf lib/src/",
     "lint": "eslint -c .eslintrc.js src/**/*.ts test/**/*.ts src/**/*.tsx",
-    "start:dev": "yarn build && node --async-stack-traces lib/index.js",
+    "start:dev": "corepack yarn build && node --async-stack-traces lib/index.js",
     "test": "ts-mocha --project ./tsconfig.json test/commands/**/*.ts",
     "test:integration": "NODE_ENV=harness ts-mocha --async-stack-traces --forbid-only --require test/integration/fixtures.ts --timeout 300000 --project ./tsconfig.json \"test/integration/**/*Test.ts\"",
-    "test:integration:single": "NODE_ENV=harness npx ts-mocha --require test/integration/fixtures.ts --timeout 300000 --project ./tsconfig.json",
+    "test:integration:single": "NODE_ENV=harness corepack npx ts-mocha --require test/integration/fixtures.ts --timeout 300000 --project ./tsconfig.json",
     "test:appservice:integration": "NODE_ENV=harness ts-mocha --async-stack-traces --forbid-only --timeout 300000 --project ./tsconfig.json \"test/appservice/integration/**/*Test.ts\"",
-    "test:appservice:integration:single": "NODE_ENV=harness npx ts-mocha --timeout 300000 --project ./tsconfig.json",
+    "test:appservice:integration:single": "NODE_ENV=harness corepack npx ts-mocha --timeout 300000 --project ./tsconfig.json",
     "test:manual": "NODE_ENV=harness ts-node test/integration/manualLaunchScript.ts",
     "version": "sed -i '/# version automated/s/[0-9][0-9]*\\.[0-9][0-9]*\\.[0-9][^\"]*/'$npm_package_version'/' synapse_antispam/setup.py && git add synapse_antispam/setup.py && cat synapse_antispam/setup.py"
   },
@@ -77,5 +77,6 @@
   },
   "engines": {
     "node": ">=18.0.0"
-  }
+  },
+  "packageManager": "yarn@1.22.22+sha1.ac34549e6aa8e7ead463a7407e1c7390f61a6610"
 }