diff --git a/README.md b/README.md
index 8ccea1b..71361e7 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,21 @@ We also try to fix bugs.
 
 The original README can be found [here](README_orig.md)
 
-## Changelog
+## Call for testers
+
+### `--experimental-backends`
+
+This flag enables the refactored/partially rewritten backends.
+
+Currently new backends features better vsync with the xrender backend, improved input lag with the glx backend (for non-NVIDIA users). The performance should be on par with the old backends.
+
+New backend features will only be implemented on the new backends from now on, and the old backends will eventually be phased out after the new backends stabilizes.
+
+To test the new backends, add the `--experimental-backends` flag to the command line you used to run compton. This flag is not available from the configuration file.
+
+To report issues with the new backends, please state explicitly you are using the new backends in your report.
+
+## Change Log
 
 See [Releases](https://github.com/yshui/compton/releases)
 
@@ -35,7 +49,7 @@ Assuming you already have all the usual building tools installed (e.g. gcc, meso
 * xcb-composite
 * xcb-image
 * xcb-present
-* xcb-xinerama (optional, disable with the `-Dxinerama=false` meson configure flag)
+* xcb-xinerama
 * pixman
 * libdbus (optional, disable with the `-Ddbus=false` meson configure flag)
 * libconfig (optional, disable with the `-Dconfig_file=false` meson configure flag)