diff --git a/_Sidebar.md b/_Sidebar.md
index 7037310..3770b68 100644
--- a/_Sidebar.md
+++ b/_Sidebar.md
@@ -7,6 +7,7 @@
 
 #### Migration Tool
 * [Migration to 0.5.0](Migration-to-0.5.0)
+* [Migration to 0.4.0](Migration-to-0.4.0)
 
 #### Technical Document
 * [Operational Transformation](Operational-Transformation)
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