diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 73ca501..261717b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -63,6 +63,10 @@ jobs:
               run: npm install
             - name: Check Types
               run: npm run test:types
+            - name: Check Types (TypeScript 5.3)
+              run: npm run test:types:5.3
+            - name: Check Types (TypeScript 5.x)
+              run: npm run test:types:5.x
     are_the_types_wrong:
         name: Are the types wrong?
         runs-on: ubuntu-latest
diff --git a/eslint.config.js b/eslint.config.js
index c67cef8..a77f92d 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -107,8 +107,9 @@ export default defineConfig([
 	{
 		name: "json/jsonc",
 		plugins: { json },
-		files: ["**/*.jsonc"],
+		files: ["**/*.jsonc", "**/tsconfig*.json"],
 		language: "json/jsonc",
+		languageOptions: { allowTrailingCommas: true },
 		extends: ["json/recommended"],
 	},
 	{
diff --git a/package.json b/package.json
index 9faf239..4cae3e4 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,10 @@
     "test": "mocha \"tests/**/*.test.js\"",
     "test:coverage": "c8 npm test",
     "test:jsr": "npx -y jsr@latest publish --dry-run",
-    "test:types": "tsc -p tests/types/tsconfig.json"
+    "test:types": "tsc -p tests/types/tsconfig.json",
+    "test:types:5.3": "npx -p typescript@5.3 -y -- tsc -p tests/types/tsconfig.legacy.json",
+    "test:types:5.x": "npx -p typescript@5.x -y -- tsc -p tests/types/tsconfig.json",
+    "test:types:all": "npm run test:types && npm run test:types:5.x && npm run test:types:5.3"
   },
   "keywords": [
     "eslint",
diff --git a/tests/types/tsconfig.json b/tests/types/tsconfig.json
index 14eb608..94376db 100644
--- a/tests/types/tsconfig.json
+++ b/tests/types/tsconfig.json
@@ -1,6 +1,8 @@
 {
   "extends": "../../tsconfig.json",
   "compilerOptions": {
+    "allowJs": false,
+    "checkJs": false,
     "noEmit": true,
     "rootDir": "../..",
     "strict": true,
@@ -11,5 +13,5 @@
     "erasableSyntaxOnly": true
   },
   "files": [],
-  "include": ["**/*.test.ts", "**/*.test.cts", "../../dist"]
+  "include": [".", "../../dist"]
 }
diff --git a/tests/types/tsconfig.legacy.json b/tests/types/tsconfig.legacy.json
new file mode 100644
index 0000000..11f712e
--- /dev/null
+++ b/tests/types/tsconfig.legacy.json
@@ -0,0 +1,17 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "allowJs": false,
+    "checkJs": false,
+    "noEmit": true,
+    "rootDir": "../..",
+    "strict": true,
+    "strictNullChecks": true,
+    "useUnknownInCatchVariables": true,
+    "exactOptionalPropertyTypes": true,
+    "verbatimModuleSyntax": true
+    // "erasableSyntaxOnly" is not supported in TypeScript < 5.8.
+  },
+  "files": [],
+  "include": [".", "../../dist"]
+}