diff --git a/libguac/Doxyfile b/libguac/Doxyfile
index 0bfde8d4..812ee0c9 100644
--- a/libguac/Doxyfile
+++ b/libguac/Doxyfile
@@ -31,7 +31,7 @@ PROJECT_NAME           = libguac
 # This could be handy for archiving the generated documentation or
 # if some version control system is used.
 
-PROJECT_NUMBER         =
+PROJECT_NUMBER         = 0.5.0
 
 # The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute)
 # base path where the generated documentation will be put.