diff --git a/features/cellular/framework/AT/AT_CellularBase.h b/features/cellular/framework/AT/AT_CellularBase.h
index dd69bc707e..e50008a75d 100644
--- a/features/cellular/framework/AT/AT_CellularBase.h
+++ b/features/cellular/framework/AT/AT_CellularBase.h
@@ -42,6 +42,11 @@ public:
      */
     device_err_t get_device_error() const;
 
+    /* Supported features by the modem
+     *
+     * NOTE! These are used as index to feature table, so the only allowed modification to this is appending
+     *       to the end (just before PROPERTY_MAX). Do not modify any of the existing fields.
+     */
     enum CellularProperty {
         PROPERTY_C_EREG,            // AT_CellularNetwork::RegistrationMode. What support modem has for this registration type.
         PROPERTY_C_GREG,            // AT_CellularNetwork::RegistrationMode. What support modem has for this registration type.
@@ -58,6 +63,7 @@ public:
         PROPERTY_IPV4V6_PDP_TYPE,   // 0 = not supported, 1 = supported. Does modem support dual stack IPV4V6?
         PROPERTY_NON_IP_PDP_TYPE,   // 0 = not supported, 1 = supported. Does modem support Non-IP?
         PROPERTY_AT_CGEREP,         // 0 = not supported, 1 = supported. Does modem support AT command AT+CGEREP.
+
         PROPERTY_MAX
     };