diff --git a/README.md b/README.md
index 10dd0e7..f37a153 100644
--- a/README.md
+++ b/README.md
@@ -259,3 +259,4 @@ DIGEdit is the text component of WindTerm.
 
 # License
 Completely FREE for personal, schools and students use without limitations.
+For testing in commercial environment, only short-term testing within 30 days is allowed. Not allowed if more than 30 days.