diff --git a/README.md b/README.md
index 12beeb8..b3c33fc 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 A library which provides support for setting the time and deployment ID of an AudioMoth using an acoustic tone.
 
+Compatible with standard AudioMoth firmware 1.5.0 and later.
+
 ## Usage ##
 
 ### Android ###