diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index aee8bb5..5636b39 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -17,8 +17,8 @@ so any savefiles should first be archived.
 Licensing
 ---------------
 
-SolveSpace is licensed under the GPLv3 and any contributions must be made available
-under the terms of that license.
+SolveSpace is licensed under the GPLv3 or later and any contributions
+must be made available under the terms of that license.
 
 Contributing translations
 -------------------------
diff --git a/README.md b/README.md
index a5bb470..9b6cb22 100644
--- a/README.md
+++ b/README.md
@@ -259,4 +259,4 @@ and debug SolveSpace.
 License
 -------
 
-SolveSpace is distributed under the terms of the [GPL v3 license](COPYING.txt).
+SolveSpace is distributed under the terms of the [GPL v3](COPYING.txt) or later.