diff --git a/CSS/addons/organizr/glass/README.md b/CSS/addons/organizr/glass/README.md
index 4b610ead..aac005db 100644
--- a/CSS/addons/organizr/glass/README.md
+++ b/CSS/addons/organizr/glass/README.md
@@ -11,6 +11,9 @@
 
 ***
 
+**NOTE:** `Firefox: From version 70: this feature is behind the layout.css.backdrop-filter.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.`
+
+
 ## Full
 
 1. Set the Organizr theme to either Aquamarine or Hotline.