diff --git a/Doxyfile b/Doxyfile
index 5907e63b..b659cc83 100644
--- a/Doxyfile
+++ b/Doxyfile
@@ -38,7 +38,7 @@ PROJECT_NAME           = "libsigrok"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = "unreleased development snapshot"
+PROJECT_NUMBER         = "0.4.0"
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a