diff --git a/docs/build.md b/docs/build.md
index 10eef6ac..a3b10b30 100644
--- a/docs/build.md
+++ b/docs/build.md
@@ -1,5 +1,11 @@
 # Build
 
+## Environments
+* npm: 4.x
+* node: 7.x
+
+You have to use `npm v4.x`, `v5.x` is not supported.
+
 ## Development
 
 We use Webpack HMR to develop Boostnote.