diff --git a/docs/0.8-upgrade.md b/docs/0.8-upgrade.md
index 2837000..efe54d8 100644
--- a/docs/0.8-upgrade.md
+++ b/docs/0.8-upgrade.md
@@ -42,6 +42,12 @@ the React production build.
 When using module processing, it should be possible to split output into several
 [modules](https://clojurescript.org/reference/compiler-options#modules).
 
+**Externs are required for use with node modules also!** React created objects
+statically in several places and then accesses those dynamically. Closure-compiler
+will in these cases rename the statically object properties, which will break
+dynamically accessing the objects. Externs fix this by defining which properties
+must not be renamed.
+
 ## Browser - loading React from CDNJS or custom Webpack bundle
 
 **TODO: Not tested properly**