diff --git a/README.txt b/README.txt
index d0fde941aef781d3f2501a63a77affb231ac77ba..5a43d6be476d5ac7ee84cb3d2cb7f600dfb7a3f1 100644
--- a/README.txt
+++ b/README.txt
@@ -14,3 +14,11 @@ the anaconda python system. See the wiki for more details,
 https://gitlab.orekit.org/orekit-labs/python-wrapper/-/wikis/home
 
 
+The sources for the java classes that allows Python subclassing are no longer in a separate package
+but integrated in a modified orekit source fork.
+
+This fork is available at:
+https://github.com/petrushy/Orekit
+
+A compiled jar and some other artifacts are available at:
+https://github.com/petrushy/orekit_python_artifacts