diff --git a/README.md b/README.md
index ab7d4e9..19a567d 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,23 @@ It comes bundled with a few optional goodies:
 
 Tap the 'edit' button and then poke around the 'load' menu to learn more.
 
+There are some gotchas to be aware of when editing such apps on a phone:
+
+* If you upgrade LÖVE you lose all your local apps and their saved settings.
+  This includes code changes. It's hard to get code changes out due to mobile
+  restrictions. I can't come up with an alternative to copy-paste. This
+  imposes a strict limit on the number of changes I'm willing to make to a
+  large app on my phone.
+
+* If you upgrade such apps after making local changes to them, you might see
+  strange errors. Local changes are written to an overlay directory, whereas
+  upgrades modify the app in place. The two locations create lots of
+  opportunity for conflicts to arise.
+
+  To mitigate this issue, such apps by default list local changes in the
+  output editor every time they run. That will hopefully act as a reminder.
+  There's also some helpers for deleting local changes in the 'scratch' page.
+
 This repo is an example of a [Freewheeling App](http://akkartik.name/freewheeling),
 designed above all to be easy to run, easy to modify and easy to share.