diff --git a/sko/__init__.py b/sko/__init__.py
index 620d294..54feb54 100644
--- a/sko/__init__.py
+++ b/sko/__init__.py
@@ -1,4 +1,4 @@
-__version__ = '0.6.4'
+__version__ = '0.6.5'
 
 from . import DE, GA, PSO, SA, ACA, AFSA, IA, tools