diff --git a/apps/er-coap-03/er-coap-03.c b/apps/er-coap-03/er-coap-03.c
index b02227ba2..af20f0b5c 100644
--- a/apps/er-coap-03/er-coap-03.c
+++ b/apps/er-coap-03/er-coap-03.c
@@ -191,7 +191,7 @@ coap_get_tid()
 }
 /*-----------------------------------------------------------------------------------*/
 void
-coap_send_message(uip_ipaddr_t *addr, uint16_t port, uint8_t *data, uint16_t length)
+coap_send_message(uip_ipaddr_t *addr, uint16_t port, const uint8_t *data, uint16_t length)
 {
   /*configure connection to reply to client*/
   uip_ipaddr_copy(&udp_conn->ripaddr, addr);
@@ -586,7 +586,7 @@ coap_get_header_etag(void *packet, const uint8_t **etag)
 }
 
 int
-coap_set_header_etag(void *packet, uint8_t *etag, size_t etag_len)
+coap_set_header_etag(void *packet, const uint8_t *etag, size_t etag_len)
 {
   ((coap_packet_t *)packet)->etag_len = MIN(COAP_ETAG_LEN, etag_len);
   memcpy(((coap_packet_t *)packet)->etag, etag, ((coap_packet_t *)packet)->etag_len);
@@ -605,9 +605,9 @@ coap_get_header_uri_host(void *packet, const char **host)
 }
 
 int
-coap_set_header_uri_host(void *packet, char *host)
+coap_set_header_uri_host(void *packet, const char *host)
 {
-  ((coap_packet_t *)packet)->uri_host = (char *) host;
+  ((coap_packet_t *)packet)->uri_host = host;
   ((coap_packet_t *)packet)->uri_host_len = strlen(host);
 
   SET_OPTION((coap_packet_t *)packet, COAP_OPTION_URI_HOST);
@@ -615,20 +615,20 @@ coap_set_header_uri_host(void *packet, char *host)
 }
 /*-----------------------------------------------------------------------------------*/
 int
-coap_get_header_location(void *packet, const char **uri)
+coap_get_header_location(void *packet, const char **location)
 {
   if (!IS_OPTION((coap_packet_t *)packet, COAP_OPTION_LOCATION_PATH)) return 0;
 
-  *uri = ((coap_packet_t *)packet)->location_path;
+  *location = ((coap_packet_t *)packet)->location_path;
   return ((coap_packet_t *)packet)->location_path_len;
 }
 
 int
-coap_set_header_location(void *packet, char *location)
+coap_set_header_location(void *packet, const char *location)
 {
   while (location[0]=='/') ++location;
 
-  ((coap_packet_t *)packet)->location_path = (char *) location;
+  ((coap_packet_t *)packet)->location_path = location;
   ((coap_packet_t *)packet)->location_path_len = strlen(location);
 
   SET_OPTION((coap_packet_t *)packet, COAP_OPTION_LOCATION_PATH);
@@ -645,11 +645,11 @@ coap_get_header_uri_path(void *packet, const char **path)
 }
 
 int
-coap_set_header_uri_path(void *packet, char *path)
+coap_set_header_uri_path(void *packet, const char *path)
 {
   while (path[0]=='/') ++path;
 
-  ((coap_packet_t *)packet)->uri_path = (char *) path;
+  ((coap_packet_t *)packet)->uri_path = path;
   ((coap_packet_t *)packet)->uri_path_len = strlen(path);
 
   SET_OPTION((coap_packet_t *)packet, COAP_OPTION_URI_PATH);
@@ -683,7 +683,7 @@ coap_get_header_token(void *packet, const uint8_t **token)
 }
 
 int
-coap_set_header_token(void *packet, uint8_t *token, size_t token_len)
+coap_set_header_token(void *packet, const uint8_t *token, size_t token_len)
 {
   ((coap_packet_t *)packet)->token_len = MIN(COAP_TOKEN_LEN, token_len);
   memcpy(((coap_packet_t *)packet)->token, token, ((coap_packet_t *)packet)->token_len);
@@ -731,7 +731,7 @@ coap_get_header_uri_query(void *packet, const char **query)
 }
 
 int
-coap_set_header_uri_query(void *packet, char *query)
+coap_set_header_uri_query(void *packet, const char *query)
 {
   while (query[0]=='?') ++query;
 
diff --git a/apps/er-coap-03/er-coap-03.h b/apps/er-coap-03/er-coap-03.h
index 169188aab..9b5f3a887 100644
--- a/apps/er-coap-03/er-coap-03.h
+++ b/apps/er-coap-03/er-coap-03.h
@@ -200,11 +200,11 @@ typedef struct {
   uint8_t etag_len;
   uint8_t etag[COAP_ETAG_LEN];
   uint8_t uri_host_len;
-  char *uri_host;
+  const char *uri_host;
   uint8_t location_path_len;
-  char *location_path;
+  const char *location_path;
   uint8_t uri_path_len;
-  char *uri_path;
+  const char *uri_path;
   uint32_t observe; /* 0-4 bytes for coap-03 */
   uint8_t token_len;
   uint8_t token[COAP_TOKEN_LEN];
@@ -213,7 +213,7 @@ typedef struct {
   uint16_t block_size;
   uint32_t block_offset;
   uint8_t uri_query_len;
-  char *uri_query;
+  const char *uri_query;
 
   uint16_t payload_len;
   uint8_t *payload;
@@ -236,7 +236,7 @@ typedef enum
 
 void coap_init_connection(uint16_t port);
 uint16_t coap_get_tid(void);
-void coap_send_message(uip_ipaddr_t *addr, uint16_t port, uint8_t *data, uint16_t length);
+void coap_send_message(uip_ipaddr_t *addr, uint16_t port, const uint8_t *data, uint16_t length);
 
 void coap_init_message(void *packet, coap_message_type_t type, uint8_t code, uint16_t tid);
 int coap_serialize_message(void *packet, uint8_t *buffer);
@@ -255,28 +255,28 @@ int coap_get_header_max_age(void *packet, uint32_t *age);
 int coap_set_header_max_age(void *packet, uint32_t age);
 
 int coap_get_header_etag(void *packet, const uint8_t **etag);
-int coap_set_header_etag(void *packet, uint8_t *etag, size_t etag_len);
+int coap_set_header_etag(void *packet, const uint8_t *etag, size_t etag_len);
 
 int coap_get_header_uri_host(void *packet, const char **host); /*CAUTION in-place string might not be 0-terminated */
-int coap_set_header_uri_host(void *packet, char *host);
+int coap_set_header_uri_host(void *packet, const char *host);
 
 int coap_get_header_location(void *packet, const char **uri); /*CAUTION in-place string might not be 0-terminated */
-int coap_set_header_location(void *packet, char *uri);
+int coap_set_header_location(void *packet, const char *uri);
 
 int coap_get_header_uri_path(void *packet, const char **uri); /*CAUTION in-place string might not be 0-terminated */
-int coap_set_header_uri_path(void *packet, char *uri);
+int coap_set_header_uri_path(void *packet, const char *uri);
 
 int coap_get_header_observe(void *packet, uint32_t *observe);
 int coap_set_header_observe(void *packet, uint32_t observe);
 
 int coap_get_header_token(void *packet, const uint8_t **token);
-int coap_set_header_token(void *packet, uint8_t *token, size_t token_len);
+int coap_set_header_token(void *packet, const uint8_t *token, size_t token_len);
 
 int coap_get_header_block(void *packet, uint32_t *num, uint8_t *more, uint16_t *size, uint32_t *offset);
 int coap_set_header_block(void *packet, uint32_t num, uint8_t more, uint16_t size);
 
 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, char *query);
+int coap_set_header_uri_query(void *packet, const char *query);
 
 int coap_get_payload(void *packet, const uint8_t **payload);
 int coap_set_payload(void *packet, uint8_t *payload, size_t length);
diff --git a/apps/er-coap-07/er-coap-07.c b/apps/er-coap-07/er-coap-07.c
index 1e3223b2e..b87fb1928 100644
--- a/apps/er-coap-07/er-coap-07.c
+++ b/apps/er-coap-07/er-coap-07.c
@@ -209,6 +209,7 @@ coap_merge_multi_option(char **dst, size_t *dst_len, uint8_t *option, size_t opt
   /* Merge multiple options. */
   if (*dst_len > 0)
   {
+    /* dst already contains an option: concatenate */
     (*dst)[*dst_len] = separator;
     *dst_len += 1;
 
@@ -219,7 +220,8 @@ coap_merge_multi_option(char **dst, size_t *dst_len, uint8_t *option, size_t opt
   }
   else
   {
-    *dst = (char *) option; /* thus pointer pointer */
+    /* dst is empty: set to option */
+    *dst = (char *) option;
     *dst_len = option_len;
   }
 }
@@ -613,7 +615,8 @@ coap_parse_message(void *packet, uint8_t *data, uint16_t data_len)
           PRINTF("Uri-Host [%.*s]\n", ((coap_packet_t *)packet)->uri_host_len, ((coap_packet_t *)packet)->uri_host);
           break;
         case COAP_OPTION_LOCATION_PATH:
-          coap_merge_multi_option(&(((coap_packet_t *)packet)->location_path), &(((coap_packet_t *)packet)->location_path_len), current_option, option_len, '/');
+          /* coap_merge_multi_option() operates in-place on the IPBUF, but final packet field should be const string -> cast to string */
+          coap_merge_multi_option( (char **) &(((coap_packet_t *)packet)->location_path), &(((coap_packet_t *)packet)->location_path_len), current_option, option_len, '/');
           PRINTF("Location-Path [%.*s]\n", ((coap_packet_t *)packet)->location_path_len, ((coap_packet_t *)packet)->location_path);
           break;
         case COAP_OPTION_URI_PORT:
@@ -621,11 +624,13 @@ coap_parse_message(void *packet, uint8_t *data, uint16_t data_len)
           PRINTF("Uri-Port [%u]\n", ((coap_packet_t *)packet)->uri_port);
           break;
         case COAP_OPTION_LOCATION_QUERY:
-          coap_merge_multi_option(&(((coap_packet_t *)packet)->location_query), &(((coap_packet_t *)packet)->location_query_len), current_option, option_len, '&');
+          /* coap_merge_multi_option() operates in-place on the IPBUF, but final packet field should be const string -> cast to string */
+          coap_merge_multi_option( (char **) &(((coap_packet_t *)packet)->location_query), &(((coap_packet_t *)packet)->location_query_len), current_option, option_len, '&');
           PRINTF("Location-Query [%.*s]\n", ((coap_packet_t *)packet)->location_query_len, ((coap_packet_t *)packet)->location_query);
           break;
         case COAP_OPTION_URI_PATH:
-          coap_merge_multi_option(&(((coap_packet_t *)packet)->uri_path), &(((coap_packet_t *)packet)->uri_path_len), current_option, option_len, '/');
+          /* coap_merge_multi_option() operates in-place on the IPBUF, but final packet field should be const string -> cast to string */
+          coap_merge_multi_option( (char **) &(((coap_packet_t *)packet)->uri_path), &(((coap_packet_t *)packet)->uri_path_len), current_option, option_len, '/');
           PRINTF("Uri-Path [%.*s]\n", ((coap_packet_t *)packet)->uri_path_len, ((coap_packet_t *)packet)->uri_path);
           break;
         case COAP_OPTION_OBSERVE:
@@ -673,7 +678,8 @@ coap_parse_message(void *packet, uint8_t *data, uint16_t data_len)
           PRINTF("Fence-Post\n");
           break;
         case COAP_OPTION_URI_QUERY:
-          coap_merge_multi_option(&(((coap_packet_t *)packet)->uri_query), &(((coap_packet_t *)packet)->uri_query_len), current_option, option_len, '&');
+          /* coap_merge_multi_option() operates in-place on the IPBUF, but final packet field should be const string -> cast to string */
+          coap_merge_multi_option( (char **) &(((coap_packet_t *)packet)->uri_query), &(((coap_packet_t *)packet)->uri_query_len), current_option, option_len, '&');
           PRINTF("Uri-Query [%.*s]\n", ((coap_packet_t *)packet)->uri_query_len, ((coap_packet_t *)packet)->uri_query);
           break;
         case COAP_OPTION_BLOCK2:
@@ -752,7 +758,7 @@ coap_set_header_content_type(void *packet, unsigned int content_type)
 }
 /*-----------------------------------------------------------------------------------*/
 int
-coap_get_header_accept(void *packet, uint16_t **accept)
+coap_get_header_accept(void *packet, const uint16_t **accept)
 {
   if (!IS_OPTION((coap_packet_t *)packet, COAP_OPTION_ACCEPT)) return 0;
 
@@ -802,7 +808,7 @@ coap_get_header_etag(void *packet, const uint8_t **etag)
 }
 
 int
-coap_set_header_etag(void *packet, uint8_t *etag, size_t etag_len)
+coap_set_header_etag(void *packet, const uint8_t *etag, size_t etag_len)
 {
   ((coap_packet_t *)packet)->etag_len = MIN(COAP_ETAG_LEN, etag_len);
   memcpy(((coap_packet_t *)packet)->etag, etag, ((coap_packet_t *)packet)->etag_len);
@@ -822,7 +828,7 @@ coap_get_header_if_match(void *packet, const uint8_t **etag)
 }
 
 int
-coap_set_header_if_match(void *packet, uint8_t *etag, size_t etag_len)
+coap_set_header_if_match(void *packet, const uint8_t *etag, size_t etag_len)
 {
   ((coap_packet_t *)packet)->if_match_len = MIN(COAP_ETAG_LEN, etag_len);
   memcpy(((coap_packet_t *)packet)->if_match, etag, ((coap_packet_t *)packet)->if_match_len);
@@ -854,7 +860,7 @@ coap_get_header_token(void *packet, const uint8_t **token)
 }
 
 int
-coap_set_header_token(void *packet, uint8_t *token, size_t token_len)
+coap_set_header_token(void *packet, const uint8_t *token, size_t token_len)
 {
   ((coap_packet_t *)packet)->token_len = MIN(COAP_TOKEN_LEN, token_len);
   memcpy(((coap_packet_t *)packet)->token, token, ((coap_packet_t *)packet)->token_len);
@@ -873,7 +879,7 @@ coap_get_header_proxy_uri(void *packet, const char **uri)
 }
 
 int
-coap_set_header_proxy_uri(void *packet, char *uri)
+coap_set_header_proxy_uri(void *packet, const char *uri)
 {
   ((coap_packet_t *)packet)->proxy_uri = uri;
   ((coap_packet_t *)packet)->proxy_uri_len = strlen(uri);
@@ -892,7 +898,7 @@ coap_get_header_uri_host(void *packet, const char **host)
 }
 
 int
-coap_set_header_uri_host(void *packet, char *host)
+coap_set_header_uri_host(void *packet, const char *host)
 {
   ((coap_packet_t *)packet)->uri_host = host;
   ((coap_packet_t *)packet)->uri_host_len = strlen(host);
@@ -911,7 +917,7 @@ coap_get_header_uri_path(void *packet, const char **path)
 }
 
 int
-coap_set_header_uri_path(void *packet, char *path)
+coap_set_header_uri_path(void *packet, const char *path)
 {
   while (path[0]=='/') ++path;
 
@@ -932,7 +938,7 @@ coap_get_header_uri_query(void *packet, const char **query)
 }
 
 int
-coap_set_header_uri_query(void *packet, char *query)
+coap_set_header_uri_query(void *packet, const char *query)
 {
   while (query[0]=='?') ++query;
 
@@ -953,7 +959,7 @@ coap_get_header_location_path(void *packet, const char **path)
 }
 
 int
-coap_set_header_location_path(void *packet, char *path)
+coap_set_header_location_path(void *packet, const char *path)
 {
   char *query;
 
@@ -985,7 +991,7 @@ coap_get_header_location_query(void *packet, const char **query)
 }
 
 int
-coap_set_header_location_query(void *packet, char *query)
+coap_set_header_location_query(void *packet, const char *query)
 {
   while (query[0]=='?') ++query;
 
diff --git a/apps/er-coap-07/er-coap-07.h b/apps/er-coap-07/er-coap-07.h
index 13c83b1e0..f7f622404 100644
--- a/apps/er-coap-07/er-coap-07.h
+++ b/apps/er-coap-07/er-coap-07.h
@@ -213,18 +213,18 @@ typedef struct {
   coap_content_type_t content_type; /* Parse options once and store; allows setting options in random order  */
   uint32_t max_age;
   size_t proxy_uri_len;
-  char *proxy_uri;
+  const char *proxy_uri;
   uint8_t etag_len;
   uint8_t etag[COAP_ETAG_LEN];
   size_t uri_host_len;
-  char *uri_host;
+  const char *uri_host;
   size_t location_path_len;
-  char *location_path;
+  const char *location_path;
   uint16_t uri_port;
   size_t location_query_len;
-  char *location_query;
+  const char *location_query;
   size_t uri_path_len;
-  char *uri_path;
+  const char *uri_path;
   uint16_t observe;
   uint8_t token_len;
   uint8_t token[COAP_TOKEN_LEN];
@@ -241,7 +241,7 @@ typedef struct {
   uint16_t block1_size;
   uint32_t block1_offset;
   size_t uri_query_len;
-  char *uri_query;
+  const char *uri_query;
   uint8_t if_none_match;
 
   uint16_t payload_len;
@@ -268,41 +268,41 @@ int coap_get_post_variable(void *packet, const char *name, const char **output);
 unsigned int coap_get_header_content_type(void *packet);
 int coap_set_header_content_type(void *packet, unsigned int content_type);
 
-int coap_get_header_accept(void *packet, uint16_t **accept);
+int coap_get_header_accept(void *packet, const uint16_t **accept);
 int coap_set_header_accept(void *packet, uint16_t accept);
 
 int coap_get_header_max_age(void *packet, uint32_t *age);
 int coap_set_header_max_age(void *packet, uint32_t age);
 
 int coap_get_header_etag(void *packet, const uint8_t **etag);
-int coap_set_header_etag(void *packet, uint8_t *etag, size_t etag_len);
+int coap_set_header_etag(void *packet, const uint8_t *etag, size_t etag_len);
 
 int coap_get_header_if_match(void *packet, const uint8_t **etag);
-int coap_set_header_if_match(void *packet, uint8_t *etag, size_t etag_len);
+int coap_set_header_if_match(void *packet, const uint8_t *etag, size_t etag_len);
 
 int coap_get_header_if_none_match(void *packet);
 int coap_set_header_if_none_match(void *packet);
 
 int coap_get_header_token(void *packet, const uint8_t **token);
-int coap_set_header_token(void *packet, uint8_t *token, size_t token_len);
+int coap_set_header_token(void *packet, const uint8_t *token, size_t token_len);
 
 int coap_get_header_proxy_uri(void *packet, const char **uri); /* In-place string might not be 0-terminated. */
-int coap_set_header_proxy_uri(void *packet, char *uri);
+int coap_set_header_proxy_uri(void *packet, const char *uri);
 
 int coap_get_header_uri_host(void *packet, const char **host); /* In-place string might not be 0-terminated. */
-int coap_set_header_uri_host(void *packet, char *host);
+int coap_set_header_uri_host(void *packet, const char *host);
 
 int coap_get_header_uri_path(void *packet, const char **path); /* In-place string might not be 0-terminated. */
-int coap_set_header_uri_path(void *packet, char *path);
+int coap_set_header_uri_path(void *packet, const char *path);
 
 int coap_get_header_uri_query(void *packet, const char **query); /* In-place string might not be 0-terminated. */
-int coap_set_header_uri_query(void *packet, char *query);
+int coap_set_header_uri_query(void *packet, const char *query);
 
 int coap_get_header_location_path(void *packet, const char **path); /* In-place string might not be 0-terminated. */
-int coap_set_header_location_path(void *packet, char *path); /* Also splits optional query into Location-Query option. */
+int coap_set_header_location_path(void *packet, const char *path); /* Also splits optional query into Location-Query option. */
 
 int coap_get_header_location_query(void *packet, const char **query); /* In-place string might not be 0-terminated. */
-int coap_set_header_location_query(void *packet, char *query);
+int coap_set_header_location_query(void *packet, const char *query);
 
 int coap_get_header_observe(void *packet, uint32_t *observe);
 int coap_set_header_observe(void *packet, uint32_t observe);
diff --git a/apps/erbium/erbium.c b/apps/erbium/erbium.c
index 007b1ee2f..53d129d8f 100644
--- a/apps/erbium/erbium.c
+++ b/apps/erbium/erbium.c
@@ -59,33 +59,6 @@ LIST(restful_services);
 LIST(restful_periodic_services);
 
 
-#ifdef WITH_HTTP
-
-char *
-rest_to_http_max_age(uint32_t age)
-{
-  /* Cache-Control: max-age=age for HTTP */
-  static char temp_age[19];
-  snprintf(temp_age, sizeof(temp_age), "max-age=%lu", age);
-  return temp_age;
-}
-
-char *
-rest_to_http_etag(uint8_t *etag, uint8_t etag_len)
-{
-  static char temp_etag[17];
-  int index = 0;
-
-  for (index = 0; index<sizeof(temp_etag) && index<etag_len; ++index) {
-    snprintf(temp_etag+2*index, sizeof(temp_etag), "%02x", etag[index]);
-  }
-  temp_etag[2*index] = '\0';
-
-  return temp_etag;
-}
-#endif /*WITH_COAP*/
-
-
 void
 rest_init_framework(void)
 {
diff --git a/apps/erbium/erbium.h b/apps/erbium/erbium.h
index 4504c5836..2ab637e3e 100644
--- a/apps/erbium/erbium.h
+++ b/apps/erbium/erbium.h
@@ -146,7 +146,7 @@ struct rest_implementation {
   /** Get request URI path */
   int (* get_url)(void *request, const char **url);
 
-  int (* set_url)(void *request, char *url);
+  int (* set_url)(void *request, const char *url);
 
   /** Get the method of a request. */
   rest_resource_flags_t (* get_method_type)(void *request);
@@ -160,7 +160,7 @@ struct rest_implementation {
   /** Set the content-type of a response. */
   int (* set_header_content_type)(void *response, unsigned int content_type);
 
-  int (* get_header_accept)(void *request, uint16_t **accept);
+  int (* get_header_accept)(void *request, const uint16_t **accept);
 
   /** Get the Max-Age option of a request. */
   int (* get_header_max_age)(void *request, uint32_t *age);
@@ -169,7 +169,7 @@ struct rest_implementation {
   int (* set_header_max_age)(void *response, uint32_t age);
 
   /** Set the ETag option of a response. */
-  int (* set_header_etag)(void *response, uint8_t *etag, size_t length);
+  int (* set_header_etag)(void *response, const uint8_t *etag, size_t length);
 
   /** Get the If-Match option of a request. */
   int (* get_header_if_match)(void *request, const uint8_t **etag);
@@ -181,7 +181,7 @@ struct rest_implementation {
   int (* get_header_host)(void *request, const char **host);
 
   /** Set the location option of a response. */
-  int (* set_header_location)(void *response, char *location);
+  int (* set_header_location)(void *response, const char *location);
 
   /** Get the payload option of a request. */
   int (* get_request_payload)(void *request, const uint8_t **payload);
diff --git a/examples/er-rest-example/Makefile b/examples/er-rest-example/Makefile
index 7bf002ebc..50678a2db 100644
--- a/examples/er-rest-example/Makefile
+++ b/examples/er-rest-example/Makefile
@@ -14,7 +14,7 @@ WITH_UIP6=1
 UIP_CONF_IPV6=1
 
 # variable for this Makefile
-# configure CoAP implementation (3|6|7)
+# configure CoAP implementation (3|7)
 WITH_COAP=7
 
 # must be CFLAGS not variables
@@ -33,12 +33,6 @@ CFLAGS += -DWITH_COAP=7
 CFLAGS += -DREST=coap_rest_implementation
 CFLAGS += -DUIP_CONF_TCP=0
 APPS += er-coap-07
-else ifeq ($(WITH_COAP), 6)
-${info INFO: compiling with CoAP-06}
-CFLAGS += -DWITH_COAP=6
-CFLAGS += -DREST=coap_rest_implementation
-CFLAGS += -DUIP_CONF_TCP=0
-APPS += er-coap-06
 else ifeq ($(WITH_COAP), 3)
 ${info INFO: compiling with CoAP-03}
 CFLAGS += -DWITH_COAP=3
@@ -50,7 +44,7 @@ ${info INFO: compiling with HTTP}
 CFLAGS += -DWITH_HTTP
 CFLAGS += -DREST=http_rest_implementation
 CFLAGS += -DUIP_CONF_TCP=1
-APPS += rest-http-engine
+APPS += er-http-engine
 endif
 
 APPS += erbium
diff --git a/examples/er-rest-example/README b/examples/er-rest-example/README
index 9a59cd8e9..3642a1b05 100644
--- a/examples/er-rest-example/README
+++ b/examples/er-rest-example/README
@@ -8,12 +8,16 @@ coap-client-example.c: A CoAP client that polls the /toggle resource every 10 se
 
 PRELIMINARIES
 -------------
-a) For convenience, define the Cooja addresses in /etc/hosts
+a) Make sure rpl-border-router has the same stack and fits into mote memory, e.g.:
+   Disable RDC in border-router project-conf.h
+   #undef NETSTACK_CONF_RDC
+   #define NETSTACK_CONF_RDC     nullrdc_driver
+b) For convenience, define the Cooja addresses in /etc/hosts
    aaaa::0212:7401:0001:0101	cooja1
    aaaa::0212:7402:0002:0202	cooja2
    ...
-b) Get the Copper CoAP browser from https://addons.mozilla.org/en-US/firefox/addon/copper-270430/
-c) Optional: Save Tmotes as default target
+c) Get the Copper CoAP browser from https://addons.mozilla.org/en-US/firefox/addon/copper-270430/
+d) Optional: Save Tmotes as default target
    $ make TARGET=sky savetarget
 
 COOJA HOWTO
@@ -26,8 +30,10 @@ Server only:
 
 With client:
 1) $ make TARGET=cooja coap-client-server-example.csc
-2) Wait until red LED toggles on mote 2 (server)
-3) Choose "Click button on Sky 3" from the context menu of mote 3 (client) and watch serial output
+2) Open new terminal
+3) $ make connect-router-cooja
+4) Wait until red LED toggles on mote 2 (server)
+5) Choose "Click button on Sky 3" from the context menu of mote 3 (client) and watch serial output
 
 TMOTES HOWTO
 ------------
@@ -50,7 +56,7 @@ Add a client:
 
 DETAILS
 -------
-The Erbium CoAP currently implements draft 07.
+The Erbium CoAP currently implements draft 08.
 Central features are commented in rest-server-example.c.
 In general, apps/er-coap-07 supports:
 * All CoAP-07 header options
@@ -60,6 +66,15 @@ In general, apps/er-coap-07 supports:
 * Resource discovery
 * Observing Resources (see EVENT_ and PRERIODIC_RESOURCE, note COAP_MAX_OBSERVERS)
 
+REST IMPLEMENTATIONS
+--------------------
+The Makefile uses WITH_COAP to configure different implementations for the Erbium REST Engine.
+* WITH_COAP=7 uses Erbium CoAP 07 apps/er-coap-07/.
+  The default port for coap-07 is 5683.
+* WITH_COAP=3 uses Erbium CoAP 03 apps/er-coap-03/.
+  The default port for coap-03 is 61616.
+* WITH_COAP=0 is a stub to link an Erbium HTTP engine that uses the same resource abstraction (REST.x() functions and RESOURCE macros. 
+
 TODOs
 -----
 * Blockwise uploads (for POST/PUT payload)
diff --git a/examples/er-rest-example/project-conf.h b/examples/er-rest-example/project-conf.h
index 017f80701..0e91bedcd 100644
--- a/examples/er-rest-example/project-conf.h
+++ b/examples/er-rest-example/project-conf.h
@@ -57,7 +57,7 @@
 
 /* Must be <= open transaction number. */
 #ifndef COAP_MAX_OBSERVERS
-#define COAP_MAX_OBSERVERS      COAP_MAX_OPEN_TRANSACTIONS
+#define COAP_MAX_OBSERVERS      COAP_MAX_OPEN_TRANSACTIONS-1
 #endif
 
 
diff --git a/examples/er-rest-example/rest-server-example.c b/examples/er-rest-example/rest-server-example.c
index d76b622c1..a1b334a5c 100644
--- a/examples/er-rest-example/rest-server-example.c
+++ b/examples/er-rest-example/rest-server-example.c
@@ -84,8 +84,6 @@
 /* For CoAP-specific example: not required for normal RESTful Web service. */
 #if WITH_COAP == 3
 #include "er-coap-03.h"
-#elif WITH_COAP == 6
-#include "er-coap-06.h"
 #elif WITH_COAP == 7
 #include "er-coap-07.h"
 #else
@@ -227,7 +225,7 @@ mirror_handler(void* request, void* response, uint8_t *buffer, uint16_t preferre
   {
     strpos += snprintf((char *)buffer+strpos, REST_MAX_CHUNK_SIZE-strpos+1, "Bl %lu%s (%u)\n", block_num, block_more ? "+" : "", block_size);
   }
-#elif WITH_COAP >= 5
+#else
   if (strpos<=REST_MAX_CHUNK_SIZE && (len = coap_get_header_location_path(request, &str)))
   {
     strpos += snprintf((char *)buffer+strpos, REST_MAX_CHUNK_SIZE-strpos+1, "LP %.*s\n", len, str);
@@ -240,15 +238,15 @@ mirror_handler(void* request, void* response, uint8_t *buffer, uint16_t preferre
   {
     strpos += snprintf((char *)buffer+strpos, REST_MAX_CHUNK_SIZE-strpos+1, "B2 %lu%s (%u)\n", block_num, block_more ? "+" : "", block_size);
   }
-  if (strpos<=REST_MAX_CHUNK_SIZE && coap_get_header_block1(request, &block_num, &block_more, &block_size, NULL)) /* This getter allows NULL pointers to get only a subset of the block parameters. */
+  /*
+   * Critical Block1 option is currently rejected by engine.
+   *
+  if (strpos<=REST_MAX_CHUNK_SIZE && coap_get_header_block1(request, &block_num, &block_more, &block_size, NULL))
   {
     strpos += snprintf((char *)buffer+strpos, REST_MAX_CHUNK_SIZE-strpos+1, "B1 %lu%s (%u)\n", block_num, block_more ? "+" : "", block_size);
   }
-#if WITH_COAP >= 7
-
-#endif
-
-#endif
+  */
+#endif /* CoAP > 03 */
 #endif /* CoAP-specific example */
 
   if (strpos<=REST_MAX_CHUNK_SIZE && (len = REST.get_query(request, &query)))
@@ -281,16 +279,13 @@ mirror_handler(void* request, void* response, uint8_t *buffer, uint16_t preferre
   coap_set_header_observe(response, 10);
 #if WITH_COAP == 3
   coap_set_header_block(response, 42, 0, 64); /* The block option might be overwritten by the framework when blockwise transfer is requested. */
-#elif WITH_COAP >= 5
+#else
   coap_set_header_proxy_uri(response, "ftp://x");
   coap_set_header_block2(response, 42, 0, 64); /* The block option might be overwritten by the framework when blockwise transfer is requested. */
   coap_set_header_block1(response, 23, 0, 16);
-#if WITH_COAP >= 7
   coap_set_header_accept(response, TEXT_PLAIN);
   coap_set_header_if_none_match(response);
-#endif
-
-#endif
+#endif /* CoAP > 03 */
 #endif /* CoAP-specific example */
 }
 #endif /* REST_RES_MIRROR */
@@ -497,7 +492,7 @@ light_handler(void* request, void* response, uint8_t *buffer, uint16_t preferred
   uint16_t light_photosynthetic = light_sensor.value(LIGHT_SENSOR_PHOTOSYNTHETIC);
   uint16_t light_solar = light_sensor.value(LIGHT_SENSOR_TOTAL_SOLAR);
 
-  uint16_t *accept = NULL;
+  const uint16_t *accept = NULL;
   int num = REST.get_header_accept(request, &accept);
 
   if ((num==0) || (num && accept[0]==REST.type.TEXT_PLAIN))
@@ -537,7 +532,7 @@ battery_handler(void* request, void* response, uint8_t *buffer, uint16_t preferr
 {
   int battery = battery_sensor.value(0);
 
-  uint16_t *accept = NULL;
+  const uint16_t *accept = NULL;
   int num = REST.get_header_accept(request, &accept);
 
   if ((num==0) || (num && accept[0]==REST.type.TEXT_PLAIN))