diff --git a/examples/mbxxx/udp-ipv6-sleep/udp-client.c b/examples/mbxxx/udp-ipv6-sleep/udp-client.c
index f19e36c7c..92a0f4caf 100644
--- a/examples/mbxxx/udp-ipv6-sleep/udp-client.c
+++ b/examples/mbxxx/udp-ipv6-sleep/udp-client.c
@@ -31,7 +31,6 @@
 #include "contiki-lib.h"
 #include "contiki-net.h"
 
-#include "sleep.h"
 #include "board-sensors.h"
 #include "board.h"
 
@@ -167,7 +166,7 @@ PROCESS_THREAD(udp_client_process, ev, data)
     if(etimer_expired(&wake_timer)){  // if timer hasn't expired do not go in deep sleep, in order to receive a response.
 		printf("Sleeping...\r\n");
 		halBoardPowerDown();//sensorsPowerDown();
-		sleep_seconds(SLEEP_INTERVAL_SECONDS); // Put system in deep sleep mode for a while.
+		clock_wait(SLEEP_INTERVAL_SECONDS * 1000); // Put system in deep sleep mode for a while.
 		halBoardPowerUp();//sensorsPowerUp();
 		printf("Awake\r\n");
     }