diff --git a/reveal.js/package.json b/reveal.js/package.json
index e089a4a..63e4b3a 100644
--- a/reveal.js/package.json
+++ b/reveal.js/package.json
@@ -25,7 +25,7 @@
     "express": "~4.19.2",
     "grunt-cli": "~0.1.13",
     "mustache": "~2.3.2",
-    "socket.io": "~1.7.4"
+    "socket.io": "~2.5.1"
   },
   "devDependencies": {
     "grunt": "~1.5.2",
diff --git a/reveal.js/plugin/multiplex/package.json b/reveal.js/plugin/multiplex/package.json
index 06d4162..e5263cb 100644
--- a/reveal.js/plugin/multiplex/package.json
+++ b/reveal.js/plugin/multiplex/package.json
@@ -13,7 +13,7 @@
     "express": "~4.19.2",
     "grunt-cli": "~0.1.13",
     "mustache": "~2.3.2",
-    "socket.io": "~1.3.7"
+    "socket.io": "~2.5.1"
   },
   "license": "MIT"
 }