diff --git a/apps/popconlaunch/README.md b/apps/popconlaunch/README.md
index 416151751..2814082a7 100644
--- a/apps/popconlaunch/README.md
+++ b/apps/popconlaunch/README.md
@@ -2,3 +2,7 @@ Popcon
 ======
 
 Display apps sorted by regular use. No config - install the app and all your launchers will sort apps by most popular, based off launch counts within the last month, and then sort them by the most recently launched app.
+
+:warning: Warning: this app overrides [`Storage.readJSON`], so may slow down your watch when using apps that perform I/O.
+
+[`Storage.readJSON`]: https://www.espruino.com/ReferenceBANGLEJS2#l_Storage_readJSON
diff --git a/apps/popconlaunch/metadata.json b/apps/popconlaunch/metadata.json
index 4088f8dc0..0ccc54d9e 100644
--- a/apps/popconlaunch/metadata.json
+++ b/apps/popconlaunch/metadata.json
@@ -3,7 +3,7 @@
   "name": "Popcon Launcher",
   "shortName": "Popcon",
   "version": "0.01",
-  "description": "Launcher modification - your launchers will display your favourite (popular) apps first",
+  "description": "Launcher modification - your launchers will display your favourite (popular) apps first. Overrides `readJSON`, may slow down your watch",
   "readme": "README.md",
   "icon": "app.png",
   "type": "bootloader",