diff --git a/src/lmic/lmic_config_preconditions.h b/src/lmic/lmic_config_preconditions.h
index 63e567cc..c3a96804 100644
--- a/src/lmic/lmic_config_preconditions.h
+++ b/src/lmic/lmic_config_preconditions.h
@@ -92,7 +92,7 @@ Revision history:
 # include CFG_TEXT_1(ARDUINO_LMIC_PROJECT_CONFIG_H)
 #endif /* ARDUINO_LMIC_PROJECT_CONFIG_H_SUPPRESS */
 
-#ifdef CFG_au921
+#if defined(CFG_au921) && !defined(CFG_au915)
 #   warning "CFG_au921 was deprecated in favour of CFG_au915. Support for CFG_au921 might be removed in the future."
 #   define CFG_au915
 #endif