diff --git a/doc/Doxyfile b/doc/Doxyfile
index da6b3e5..ddd3e86 100644
--- a/doc/Doxyfile
+++ b/doc/Doxyfile
@@ -32,7 +32,7 @@ PROJECT_NAME           = ctools
 # This could be handy for archiving the generated documentation or
 # if some version control system is used.
 
-PROJECT_NUMBER         = 1.0.0
+PROJECT_NUMBER         = 0.9.0
 
 # 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