diff --git a/README.md b/README.md
index 66d928c1910506afc14e0f467d431b148905c8d9..bd2a52e3eb42003e63ef91e86c69843a948fa0a9 100644
--- a/README.md
+++ b/README.md
@@ -137,6 +137,9 @@ modules in separate folders.
   infrastructure. These modules are not installed by `make install`, and should
   not be imported.
 
+Note that the unstable and deprecated packages are not released, so they only
+exist in the development version of Iris.
+
 ## Case Studies
 
 The following is a (probably incomplete) list of case studies that use Iris, and