diff --git a/README.md b/README.md
index 708f7f3..532911d 100644
--- a/README.md
+++ b/README.md
@@ -240,6 +240,7 @@ Heat meter Techem Compact V (compact5) (non-standard protocol)
 Heat meter Techem Vario 4 (vario451) (non-standard protocol)
 Heat meter Kamstrup Multical 302 (multical302) (in C1 mode, please open issue for T1 mode)
 Heat and Cooling meter Kamstrup Multical 403 (multical403) (in C1 mode)
+Heat and Cooling meter Kamstrup Multical 603 (multical403) (in C1 mode) (work in progress)
 
 Supported room sensors:
 Bmeters RFM-AMB Thermometer/Hygrometer (rfmamb)