diff --git a/reference-implementation/package.json b/reference-implementation/package.json
index e07e8f5ff..823350ed9 100644
--- a/reference-implementation/package.json
+++ b/reference-implementation/package.json
@@ -18,7 +18,7 @@
     "eslint": "^6.8.0",
     "minimatch": "^3.0.4",
     "opener": "^1.5.1",
-    "webidl2js": "^17.1.0",
+    "webidl2js": "^18.0.0",
     "wpt-runner": "^5.0.0"
   }
 }
diff --git a/reference-implementation/web-platform-tests b/reference-implementation/web-platform-tests
index 7eaf605c3..9b03282a9 160000
--- a/reference-implementation/web-platform-tests
+++ b/reference-implementation/web-platform-tests
@@ -1 +1 @@
-Subproject commit 7eaf605c38d80377c717828376deabad86b702b2
+Subproject commit 9b03282a99ef2314c1c2d5050a105a74a2940019