diff --git a/functions/grapher/thumbnail/[slug].ts b/functions/grapher/thumbnail/[slug].ts
index 76e46f8f637..b8bcbadaae0 100644
--- a/functions/grapher/thumbnail/[slug].ts
+++ b/functions/grapher/thumbnail/[slug].ts
@@ -42,7 +42,7 @@ export const onRequestGet: PagesFunction = async (ctx) => {
     console.log("Handling", request.url, request.headers.get("User-Agent"))
 
     return router
-        .handle(request, url, { ...env, url }, ctx)
+        .fetch(request, url, { ...env, url }, ctx)
         .then((resp: Response) => {
             if (shouldCache) {
                 resp.headers.set(
diff --git a/functions/package.json b/functions/package.json
index 88b5addb457..7b58e924fd9 100644
--- a/functions/package.json
+++ b/functions/package.json
@@ -4,7 +4,7 @@
     "@cloudflare/pages-plugin-sentry": "^1.1.1",
     "@ourworldindata/grapher": "workspace:^",
     "@ourworldindata/utils": "workspace:^",
-    "itty-router": "^4.0.23",
+    "itty-router": "^5.0.17",
     "stripe": "^14.20.0",
     "svg2png-wasm": "^1.4.1"
   },
diff --git a/yarn.lock b/yarn.lock
index fe49f2f821d..997919caaf3 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -12536,10 +12536,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"itty-router@npm:^4.0.23":
-  version: 4.0.23
-  resolution: "itty-router@npm:4.0.23"
-  checksum: 10/b412f80f7d3bf78293144a43c47053c9873c98565e58aa188a66306cc6018ad3801fa157b0d694e9e1719cbc0424fcd89951f1916699eff6606f30b0645afa3e
+"itty-router@npm:^5.0.17":
+  version: 5.0.17
+  resolution: "itty-router@npm:5.0.17"
+  checksum: 10/5af87433b7ce1dc5c72c70bbf75e9676082381e6c101ac14fd5621e9d8a7e25cae97506b8654812b508d7f717aa8a881393888b4091112e33089d7b1aabd53d3
   languageName: node
   linkType: hard
 
@@ -15515,7 +15515,7 @@ __metadata:
     "@cloudflare/workers-types": "npm:^4.20240614.0"
     "@ourworldindata/grapher": "workspace:^"
     "@ourworldindata/utils": "workspace:^"
-    itty-router: "npm:^4.0.23"
+    itty-router: "npm:^5.0.17"
     stripe: "npm:^14.20.0"
     svg2png-wasm: "npm:^1.4.1"
   languageName: unknown