diff --git a/README.md b/README.md
index e0b7482..4050c95 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ However, changing the pipeline to work with other clusters should be relatively
 The following are required.
 
  * python 2.7
- - Dendropy 3.12 or later
+ - Dendropy 3.12 (note that Dendropy 4.0 or later will not work). 
  - java