diff --git a/apps/iap/iap-lingo4.c b/apps/iap/iap-lingo4.c
index fa01966..017351b 100644
--- a/apps/iap/iap-lingo4.c
+++ b/apps/iap/iap-lingo4.c
@@ -1873,15 +1873,28 @@ void iap_handlepkt_mode4(const unsigned int len, const unsigned char *buf)
              *  3     0x04  Lingo ID: Extended Interface lingo
              *  4     0x00  Command ID (bits 15:8)
              *  5     0x26  Command ID (bits 7:0)
+             *
+             *  2 byte version:
              *  6     0xNN  The state of play status change notifications.
              *            Possible values are:
              *              0x00 = Disable all change notification
              *              0x01 = Enable all change notification
              *              0x02 - 0xFF = Reserved
              *  7     0xNN   Telegram payload checksum byte
+             *
+             *  4 byte version (len == 7):
+             *  6-9   0xNN  bitmask
              */
         {
-            device.do_notify = buf[3] ? true : false;
+            if (len == 7)
+            {
+                // simplistic check whether or not to notify at all
+                device.do_notify = (buf[3] | buf[4] | buf[5] | buf[6]) ? true : false;
+            }
+            else
+            {
+                device.do_notify = buf[3] ? true : false;
+            }
             /* respond with cmd ok packet */
             cmd_ok(cmd);
             break;