diff --git a/apps/er-coap-03/er-coap-03-engine.c b/apps/er-coap-03/er-coap-03-engine.c
index 048261349..8e21d30d3 100644
--- a/apps/er-coap-03/er-coap-03-engine.c
+++ b/apps/er-coap-03/er-coap-03-engine.c
@@ -484,6 +484,8 @@ const struct rest_implementation coap_rest_implementation = {
     coap_get_header_content_type,
     coap_set_header_content_type,
     NULL,
+    NULL,
+    NULL,
     coap_get_header_max_age,
     coap_set_header_max_age,
     coap_set_header_etag,
@@ -518,8 +520,9 @@ const struct rest_implementation coap_rest_implementation = {
       METHOD_NOT_ALLOWED_405,
       NOT_FOUND_404,
       METHOD_NOT_ALLOWED_405,
+      UNSUPPORTED_MEDIA_TYPE_415,
       BAD_REQUEST_400,
-      UNSUPPORTED_MADIA_TYPE_415,
+      UNSUPPORTED_MEDIA_TYPE_415,
 
       INTERNAL_SERVER_ERROR_500,
       CRITICAL_OPTION_NOT_SUPPORTED,
diff --git a/apps/er-coap-03/er-coap-03-observing.c b/apps/er-coap-03/er-coap-03-observing.c
index dc8fbc048..a55c31691 100644
--- a/apps/er-coap-03/er-coap-03-observing.c
+++ b/apps/er-coap-03/er-coap-03-observing.c
@@ -122,39 +122,47 @@ coap_remove_observer_by_token(uip_ipaddr_t *addr, uint16_t port, uint8_t *token,
 }
 /*-----------------------------------------------------------------------------------*/
 void
-coap_notify_observers(const char *url, int type, uint32_t observe, uint8_t *payload, size_t payload_len)
+coap_notify_observers(resource_t *resource, uint16_t obs_counter, void *notification)
 {
+  coap_packet_t *const coap_res = (coap_packet_t *) notification;
   coap_observer_t* obs = NULL;
+  uint8_t preferred_type = coap_res->type;
+
+  PRINTF("Observing: Notification from %s\n", resource->url);
+
+  /* Iterate over observers. */
   for (obs = (coap_observer_t*)list_head(observers_list); obs; obs = obs->next)
   {
-    if (obs->url==url) /* using RESOURCE url string as handle */
+    if (obs->url==resource->url) /* using RESOURCE url pointer as handle */
     {
       coap_transaction_t *transaction = NULL;
 
-      /*TODO implement special transaction for CON, sharing the same buffer to allow for more observers */
+      /*TODO implement special transaction for CON, sharing the same buffer to allow for more observers. */
 
       if ( (transaction = coap_new_transaction(coap_get_tid(), &obs->addr, obs->port)) )
       {
+        PRINTF("           Observer ");
+        PRINT6ADDR(&obs->addr);
+        PRINTF(":%u\n", obs->port);
+
+        /* Prepare response */
+        coap_res->tid = transaction->tid;
+        coap_set_header_observe(coap_res, obs_counter);
+        coap_set_header_token(coap_res, obs->token, obs->token_len);
+
         /* Use CON to check whether client is still there/interested after COAP_OBSERVING_REFRESH_INTERVAL. */
         if (stimer_expired(&obs->refresh_timer))
         {
-          PRINTF("Observing: Refresh client with CON\n");
-          type = COAP_TYPE_CON;
+          PRINTF("           Refreshing with CON\n");
+          coap_res->type = COAP_TYPE_CON;
           stimer_restart(&obs->refresh_timer);
         }
+        else
+        {
+          coap_res->type = preferred_type;
+        }
 
-        /* prepare response */
-        coap_packet_t push[1]; /* This way the packet can be treated as pointer as usual. */
-        coap_init_message(push, (coap_message_type_t)type, OK_200, transaction->tid );
-        coap_set_header_observe(push, observe);
-        coap_set_header_token(push, obs->token, obs->token_len);
-        coap_set_payload(push, payload, payload_len);
-        transaction->packet_len = coap_serialize_message(push, transaction->packet);
-
-        PRINTF("Observing: Notify from /%s for ", url);
-        PRINT6ADDR(&obs->addr);
-        PRINTF(":%u\n", obs->port);
-        PRINTF("  %.*s\n", payload_len, payload);
+        transaction->packet_len = coap_serialize_message(coap_res, transaction->packet);
 
         coap_send_transaction(transaction);
       }
diff --git a/apps/er-coap-03/er-coap-03-observing.h b/apps/er-coap-03/er-coap-03-observing.h
index 287c11e9f..48cae5f92 100644
--- a/apps/er-coap-03/er-coap-03-observing.h
+++ b/apps/er-coap-03/er-coap-03-observing.h
@@ -69,7 +69,7 @@ coap_observer_t *coap_add_observer(uip_ipaddr_t *addr, uint16_t port, const uint
 void coap_remove_observer(coap_observer_t *o);
 int coap_remove_observer_by_client(uip_ipaddr_t *addr, uint16_t port);
 int coap_remove_observer_by_token(uip_ipaddr_t *addr, uint16_t port, uint8_t *token, size_t token_len);
-void coap_notify_observers(const char *url, int type, uint32_t observe, uint8_t *payload, size_t payload_len);
+void coap_notify_observers(resource_t *resource, uint16_t obs_counter, void *notification);
 
 void coap_observe_handler(resource_t *resource, void *request, void *response);
 
diff --git a/apps/er-coap-03/er-coap-03.c b/apps/er-coap-03/er-coap-03.c
index 4f7a5b81c..8a770282b 100644
--- a/apps/er-coap-03/er-coap-03.c
+++ b/apps/er-coap-03/er-coap-03.c
@@ -745,7 +745,7 @@ coap_set_header_uri_query(void *packet, const char *query)
 /*- PAYLOAD -------------------------------------------------------------------------*/
 /*-----------------------------------------------------------------------------------*/
 int
-coap_get_payload(void *packet, uint8_t **payload)
+coap_get_payload(void *packet, const uint8_t **payload)
 {
   if (((coap_packet_t *)packet)->payload) {
     *payload = ((coap_packet_t *)packet)->payload;
diff --git a/apps/er-coap-03/er-coap-03.h b/apps/er-coap-03/er-coap-03.h
index ebd2f164f..00a292bcb 100644
--- a/apps/er-coap-03/er-coap-03.h
+++ b/apps/er-coap-03/er-coap-03.h
@@ -120,7 +120,7 @@ typedef enum {
   BAD_REQUEST_400 = 160,
   NOT_FOUND_404 = 164,
   METHOD_NOT_ALLOWED_405 = 165,
-  UNSUPPORTED_MADIA_TYPE_415 = 175,
+  UNSUPPORTED_MEDIA_TYPE_415 = 175,
   INTERNAL_SERVER_ERROR_500 = 200,
   BAD_GATEWAY_502 = 202,
   SERVICE_UNAVAILABLE_503 = 203,
@@ -278,7 +278,7 @@ int coap_set_header_block(void *packet, uint32_t num, uint8_t more, uint16_t siz
 int coap_get_header_uri_query(void *packet, const char **query); /*CAUTION in-place string might not be 0-terminated */
 int coap_set_header_uri_query(void *packet, const char *query);
 
-int coap_get_payload(void *packet, uint8_t **payload);
+int coap_get_payload(void *packet, const uint8_t **payload);
 int coap_set_payload(void *packet, const void *payload, size_t length);
 
 #endif /* COAP_03_H_ */
diff --git a/apps/er-coap-07/er-coap-07-engine.c b/apps/er-coap-07/er-coap-07-engine.c
index 483f0309d..28f7f459c 100644
--- a/apps/er-coap-07/er-coap-07-engine.c
+++ b/apps/er-coap-07/er-coap-07-engine.c
@@ -537,6 +537,8 @@ const struct rest_implementation coap_rest_implementation = {
   coap_get_header_content_type,
   coap_set_header_content_type,
   coap_get_header_accept,
+  NULL,
+  NULL,
   coap_get_header_max_age,
   coap_set_header_max_age,
   coap_set_header_etag,
@@ -564,14 +566,17 @@ const struct rest_implementation coap_rest_implementation = {
     CHANGED_2_04,
     DELETED_2_02,
     VALID_2_03,
+    
     BAD_REQUEST_4_00,
     UNAUTHORIZED_4_01,
     BAD_OPTION_4_02,
     FORBIDDEN_4_03,
     NOT_FOUND_4_04,
     METHOD_NOT_ALLOWED_4_05,
+    NOT_ACCEPTABLE_4_06,
     REQUEST_ENTITY_TOO_LARGE_4_13,
-    UNSUPPORTED_MADIA_TYPE_4_15,
+    UNSUPPORTED_MEDIA_TYPE_4_15,
+    
     INTERNAL_SERVER_ERROR_5_00,
     NOT_IMPLEMENTED_5_01,
     BAD_GATEWAY_5_02,
diff --git a/apps/er-coap-07/er-coap-07.c b/apps/er-coap-07/er-coap-07.c
index 66bf40b8c..4bf995c97 100644
--- a/apps/er-coap-07/er-coap-07.c
+++ b/apps/er-coap-07/er-coap-07.c
@@ -1177,7 +1177,7 @@ coap_set_header_block1(void *packet, uint32_t num, uint8_t more, uint16_t size)
 /*- PAYLOAD -------------------------------------------------------------------------*/
 /*-----------------------------------------------------------------------------------*/
 int
-coap_get_payload(void *packet, uint8_t **payload)
+coap_get_payload(void *packet, const uint8_t **payload)
 {
   coap_packet_t *const coap_pkt = (coap_packet_t *) packet;
 
diff --git a/apps/er-coap-07/er-coap-07.h b/apps/er-coap-07/er-coap-07.h
index 2284f0a00..4749a5f50 100644
--- a/apps/er-coap-07/er-coap-07.h
+++ b/apps/er-coap-07/er-coap-07.h
@@ -129,9 +129,10 @@ typedef enum {
   FORBIDDEN_4_03 = 131,                 /* FORBIDDEN */
   NOT_FOUND_4_04 = 132,                 /* NOT_FOUND */
   METHOD_NOT_ALLOWED_4_05 = 133,        /* METHOD_NOT_ALLOWED */
+  NOT_ACCEPTABLE_4_06 = 134,            /* NOT_ACCEPTABLE */
   PRECONDITION_FAILED_4_12 = 140,       /* BAD_REQUEST */
   REQUEST_ENTITY_TOO_LARGE_4_13 = 141,  /* REQUEST_ENTITY_TOO_LARGE */
-  UNSUPPORTED_MADIA_TYPE_4_15 = 143,    /* UNSUPPORTED_MADIA_TYPE */
+  UNSUPPORTED_MEDIA_TYPE_4_15 = 143,    /* UNSUPPORTED_MEDIA_TYPE */
 
   INTERNAL_SERVER_ERROR_5_00 = 160,     /* INTERNAL_SERVER_ERROR */
   NOT_IMPLEMENTED_5_01 = 161,           /* NOT_IMPLEMENTED */
@@ -315,7 +316,7 @@ int coap_set_header_block2(void *packet, uint32_t num, uint8_t more, uint16_t si
 int coap_get_header_block1(void *packet, uint32_t *num, uint8_t *more, uint16_t *size, uint32_t *offset);
 int coap_set_header_block1(void *packet, uint32_t num, uint8_t more, uint16_t size);
 
-int coap_get_payload(void *packet, uint8_t **payload);
+int coap_get_payload(void *packet, const uint8_t **payload);
 int coap_set_payload(void *packet, const void *payload, size_t length);
 
 #endif /* COAP_07_H_ */
diff --git a/examples/er-rest-example/er-example-server.c b/examples/er-rest-example/er-example-server.c
index d9835b1d0..4bdfb7ba2 100644
--- a/examples/er-rest-example/er-example-server.c
+++ b/examples/er-rest-example/er-example-server.c
@@ -440,7 +440,7 @@ separate_finalize_handler()
       coap_packet_t response[1]; /* This way the packet can be treated as pointer as usual. */
 
       /* Restore the request information for the response. */
-      coap_separate_resume(response, &separate_store->request_metadata, CONTENT_2_05);
+      coap_separate_resume(response, &separate_store->request_metadata, REST.status.OK);
 
       coap_set_payload(response, separate_store->buffer, strlen(separate_store->buffer));
 
@@ -505,7 +505,7 @@ pushing_periodic_handler(resource_t *r)
 
   /* Build notification. */
   coap_packet_t notification[1]; /* This way the packet can be treated as pointer as usual. */
-  coap_init_message(notification, COAP_TYPE_NON, CONTENT_2_05, 0 );
+  coap_init_message(notification, COAP_TYPE_NON, REST.status.OK, 0 );
   coap_set_payload(notification, content, snprintf(content, sizeof(content), "TICK %u", obs_counter));
 
   /* Notify the registered observers with the given message type, observe option, and payload. */
@@ -547,7 +547,7 @@ event_event_handler(resource_t *r)
 
   /* Build notification. */
   coap_packet_t notification[1]; /* This way the packet can be treated as pointer as usual. */
-  coap_init_message(notification, COAP_TYPE_CON, CONTENT_2_05, 0 );
+  coap_init_message(notification, COAP_TYPE_CON, REST.status.OK, 0 );
   coap_set_payload(notification, content, snprintf(content, sizeof(content), "EVENT %u", event_counter));
 
   /* Notify the registered observers with the given message type, observe option, and payload. */
diff --git a/examples/er-rest-example/er-plugtest-server.c b/examples/er-rest-example/er-plugtest-server.c
index ac91f4cf5..55fb7fd95 100644
--- a/examples/er-rest-example/er-plugtest-server.c
+++ b/examples/er-rest-example/er-plugtest-server.c
@@ -627,7 +627,10 @@ path_handler(void* request, void* response, uint8_t *buffer, uint16_t preferred_
 
 #if REST_RES_SEPARATE
 /* Required to manually (=not by the engine) handle the response transaction. */
-#if WITH_COAP == 12
+#if WITH_COAP == 7
+#include "er-coap-07-separate.h"
+#include "er-coap-07-transactions.h"
+#elif WITH_COAP == 12
 #include "er-coap-12-separate.h"
 #include "er-coap-12-transactions.h"
 #elif WITH_COAP == 13