diff --git a/c/include/proton/disposition.h b/c/include/proton/disposition.h
index db0d1cea6..4965b2fd6 100644
--- a/c/include/proton/disposition.h
+++ b/c/include/proton/disposition.h
@@ -90,6 +90,12 @@ typedef struct pn_disposition_t pn_disposition_t;
  */
 #define PN_MODIFIED (0x0000000000000027)
 
+/**
+ * The PN_TRANSACTIONAL_STATE delivery state is a non terminal state
+ * indicating the transactional state of a delivery.
+ */
+#define PN_TRANSACTIONAL_STATE (0x0000000000000034)
+
 /**
  * Get the type of a disposition.
  *
@@ -234,6 +240,7 @@ PN_EXTERN pn_data_t *pn_disposition_annotations(pn_disposition_t *disposition);
 typedef struct pn_received_disposition_t pn_received_disposition_t;
 typedef struct pn_rejected_disposition_t pn_rejected_disposition_t;
 typedef struct pn_modified_disposition_t pn_modified_disposition_t;
+typedef struct pn_transactional_disposition_t pn_transactional_disposition_t;
 typedef struct pn_custom_disposition_t pn_custom_disposition_t;
 
 /**
@@ -254,6 +261,7 @@ PN_EXTERN pn_custom_disposition_t *pn_custom_disposition(pn_disposition_t *dispo
 PN_EXTERN pn_received_disposition_t *pn_received_disposition(pn_disposition_t *disposition);
 PN_EXTERN pn_rejected_disposition_t *pn_rejected_disposition(pn_disposition_t *disposition);
 PN_EXTERN pn_modified_disposition_t *pn_modified_disposition(pn_disposition_t *disposition);
+PN_EXTERN pn_transactional_disposition_t *pn_transactional_disposition(pn_disposition_t *disposition);
 
 /**
  * Access the disposition as a raw pn_data_t.
@@ -383,6 +391,17 @@ PN_EXTERN void pn_modified_disposition_set_undeliverable(pn_modified_disposition
  */
 PN_EXTERN pn_data_t *pn_modified_disposition_annotations(pn_modified_disposition_t *disposition);
 
+
+PN_EXTERN pn_bytes_t pn_transactional_disposition_get_id(pn_transactional_disposition_t *disposition);
+PN_EXTERN void pn_transactional_disposition_set_id(pn_transactional_disposition_t *disposition, pn_bytes_t id);
+PN_EXTERN uint64_t pn_transactional_disposition_get_outcome_type(pn_transactional_disposition_t *disposition);
+
+/**
+ * Set the provisional outcome of the message if the transaction is committed successfully.
+ * Only terminal disposition states are allowed (PN_ACCEPTED, PN_REJECTED, PN_RELEASED, PN_MODIFIED)
+ */
+PN_EXTERN void pn_transactional_disposition_set_outcome_type(pn_transactional_disposition_t *disposition, uint64_t outcome);
+
 /**
  * @}
  */
diff --git a/c/src/core/emitters.h b/c/src/core/emitters.h
index 2cd59a64c..f20bdff10 100644
--- a/c/src/core/emitters.h
+++ b/c/src/core/emitters.h
@@ -647,6 +647,19 @@ static inline void emit_modified_disposition(pni_emitter_t* emitter, pni_compoun
   }
 }
 
+static inline void emit_disposition(pni_emitter_t* emitter, pni_compound_context* compound0, pn_disposition_t *disposition);
+
+static inline void emit_transactional_disposition(pni_emitter_t* emitter, pni_compound_context* compound0, pn_transactional_disposition_t *disposition){
+  for (bool small_encoding = true; ; small_encoding = false) {
+    pni_compound_context c = emit_list(emitter, compound0, small_encoding, true);
+    pni_compound_context compound = c;
+    emit_binary_bytes(emitter, &compound, disposition->id);
+    emit_raw(emitter, &compound, disposition->outcome_raw);
+    emit_end_list(emitter, &compound, small_encoding);
+    if (encode_succeeded(emitter, &compound)) break;
+  }
+}
+
 static inline void emit_custom_disposition(pni_emitter_t* emitter, pni_compound_context* compound0, pn_custom_disposition_t *disposition){
   emit_descriptor(emitter, compound0, disposition->type);
   if ((disposition->data && pn_data_size(disposition->data) == 0) ||
@@ -687,6 +700,10 @@ static inline void emit_disposition(pni_emitter_t* emitter, pni_compound_context
       emit_descriptor(emitter, compound0, AMQP_DESC_MODIFIED);
       emit_modified_disposition(emitter, compound0, &disposition->u.s_modified);
       return;
+    case PN_DISP_TRANSACTIONAL:
+      emit_descriptor(emitter, compound0, AMQP_DESC_TRANSACTIONAL_STATE);
+      emit_transactional_disposition(emitter, compound0, &disposition->u.s_transactional);
+      return;
     case PN_DISP_CUSTOM:
       emit_custom_disposition(emitter, compound0, &disposition->u.s_custom);
       return;
diff --git a/c/src/core/engine-internal.h b/c/src/core/engine-internal.h
index da563813a..f10e6a8f0 100644
--- a/c/src/core/engine-internal.h
+++ b/c/src/core/engine-internal.h
@@ -341,6 +341,7 @@ typedef enum pn_disposition_type_t {
   PN_DISP_REJECTED = PN_REJECTED,
   PN_DISP_RELEASED = PN_RELEASED,
   PN_DISP_MODIFIED = PN_MODIFIED,
+  PN_DISP_TRANSACTIONAL = PN_TRANSACTIONAL_STATE,
 } pn_disposition_type_t;
 
 struct pn_received_disposition_t {
@@ -359,6 +360,11 @@ struct pn_modified_disposition_t {
   bool undeliverable;
 };
 
+struct pn_transactional_disposition_t {
+  pn_bytes_t id;
+  pn_bytes_t outcome_raw;
+};
+
 struct pn_custom_disposition_t {
   pn_data_t *data;
   pn_bytes_t data_raw;
@@ -370,6 +376,7 @@ struct pn_disposition_t {
     struct pn_received_disposition_t s_received;
     struct pn_rejected_disposition_t s_rejected;
     struct pn_modified_disposition_t s_modified;
+    struct pn_transactional_disposition_t s_transactional;
     struct pn_custom_disposition_t   s_custom;
   } u;
   uint16_t type;
diff --git a/c/src/core/engine.c b/c/src/core/engine.c
index 7ccb308b9..597151642 100644
--- a/c/src/core/engine.c
+++ b/c/src/core/engine.c
@@ -27,6 +27,7 @@
 #include "consumers.h"
 #include "core/frame_consumers.h"
 #include "emitters.h"
+#include "core/frame_generators.h"
 #include "fixed_string.h"
 #include "framing.h"
 #include "memory.h"
@@ -1597,6 +1598,10 @@ static void pn_disposition_finalize(pn_disposition_t *ds)
       pn_data_free(ds->u.s_custom.data);
       pn_bytes_free(ds->u.s_custom.data_raw);
       break;
+    case PN_DISP_TRANSACTIONAL:
+      pn_bytes_free(ds->u.s_transactional.id);
+      pn_bytes_free(ds->u.s_transactional.outcome_raw);
+      break;
   }
 }
 
@@ -1868,6 +1873,9 @@ void pni_disposition_to_raw(pn_disposition_t *disposition) {
     case PN_DISP_MODIFIED:
       emit_modified_disposition(&emitter, &compound, &disposition->u.s_modified);
       break;
+    case PN_DISP_TRANSACTIONAL:
+      emit_transactional_disposition(&emitter, &compound, &disposition->u.s_transactional);
+      break;
   }
 
   if (type != PN_DISP_EMPTY) {
@@ -2005,6 +2013,13 @@ pn_modified_disposition_t *pn_modified_disposition(pn_disposition_t *disposition
   return &disposition->u.s_modified;
 }
 
+pn_transactional_disposition_t *pn_transactional_disposition(pn_disposition_t *disposition)
+{
+  if (disposition->type==PN_DISP_EMPTY) disposition->type = PN_DISP_TRANSACTIONAL;
+  else if (disposition->type!=PN_DISP_TRANSACTIONAL) return NULL;
+  return &disposition->u.s_transactional;
+}
+
 pn_data_t *pn_custom_disposition_data(pn_custom_disposition_t *disposition)
 {
   assert(disposition);
@@ -2084,6 +2099,44 @@ pn_data_t *pn_modified_disposition_annotations(pn_modified_disposition_t *dispos
   return disposition->annotations;
 }
 
+pn_bytes_t pn_transactional_disposition_get_id(pn_transactional_disposition_t *disposition)
+{
+  assert(disposition);
+  return disposition->id;
+}
+
+void pn_transactional_disposition_set_id(pn_transactional_disposition_t *disposition, pn_bytes_t id)
+{
+  assert(disposition);
+  pn_bytes_free(disposition->id);
+  disposition->id = pn_bytes_dup(id);
+}
+
+uint64_t pn_transactional_disposition_get_outcome_type(pn_transactional_disposition_t *disposition)
+{
+  assert(disposition);
+  if (disposition->outcome_raw.size) {
+    bool qtype = false;
+    uint64_t type;
+    pn_amqp_decode_DQLq(disposition->outcome_raw, &qtype, &type);
+    if (qtype) {
+      return type;
+    }
+  }
+  return PN_DISP_EMPTY;
+}
+
+void pn_transactional_disposition_set_outcome_type(pn_transactional_disposition_t *disposition, uint64_t type)
+{
+  assert(disposition);
+  // Generate a described LiST0 directly - this needs a max of 11 bytes
+  char outcome_scratch[11];
+  pn_rwbytes_t scratch = {.size=sizeof(outcome_scratch), .start=outcome_scratch};
+  pn_bytes_t outcome_raw = pn_amqp_encode_DLEe(&scratch, type);
+  pn_bytes_free(disposition->outcome_raw);
+  disposition->outcome_raw = pn_bytes_dup(outcome_raw);
+}
+
 pn_delivery_tag_t pn_delivery_tag(pn_delivery_t *delivery)
 {
   if (delivery) {
@@ -2804,6 +2857,7 @@ const char *pn_disposition_type_name(uint64_t d) {
    case PN_REJECTED: return "rejected";
    case PN_RELEASED: return "released";
    case PN_MODIFIED: return "modified";
+   case PN_TRANSACTIONAL_STATE: return "transactional_state";
    default: return "unknown";
   }
 }
diff --git a/c/src/core/transport.c b/c/src/core/transport.c
index 892e430c1..98d015e63 100644
--- a/c/src/core/transport.c
+++ b/c/src/core/transport.c
@@ -1602,6 +1602,20 @@ static void pni_amqp_decode_disposition (uint64_t type, pn_bytes_t disp_data, pn
       }
       break;
     }
+    case AMQP_DESC_TRANSACTIONAL_STATE: {
+      pn_bytes_t id;
+      bool qoutcome;
+      pn_bytes_t outcome_raw;
+      pn_amqp_decode_DqEzQRe(disp_data, &id, &qoutcome, &outcome_raw);
+      disp->type = PN_DISP_TRANSACTIONAL;
+      pn_bytes_free(disp->u.s_transactional.id);
+      disp->u.s_transactional.id = pn_bytes_dup(id);
+      disp->u.s_transactional.outcome_raw = (pn_bytes_t){0, NULL};
+      if (qoutcome) {
+        disp->u.s_transactional.outcome_raw = pn_bytes_dup(outcome_raw);
+      }
+      break;
+    }
     default: {
       pn_bytes_t data_raw = (pn_bytes_t){0, NULL};
       pn_amqp_decode_DqR(disp_data, &data_raw);
diff --git a/c/tools/codec-generator/specs.json b/c/tools/codec-generator/specs.json
index dddf6d6f8..82b4a013f 100644
--- a/c/tools/codec-generator/specs.json
+++ b/c/tools/codec-generator/specs.json
@@ -2,6 +2,7 @@
   "fill_specs": [
     "R",
     "DLR",
+    "DL[]",
     "DL[c]",
     "DL[?HIIII]",
     "DL[?IIII?I?I?In?o]",
@@ -44,6 +45,7 @@
     "D.[s]",
     "D.[z]",
     "D.[Bz]",
+    "D.[z?R]",
     "D.[R]",
     "D?L.",
     "D?L?."
diff --git a/sasl_conf/proton-server.conf b/sasl_conf/proton-server.conf
new file mode 100644
index 000000000..15f683a44
--- /dev/null
+++ b/sasl_conf/proton-server.conf
@@ -0,0 +1,4 @@
+
+sasldb_path: /home/andrew/Work/proton/src-jj/sasl_conf/proton.sasldb
+mech_list: EXTERNAL DIGEST-MD5 SCRAM-SHA-1 CRAM-MD5 PLAIN ANONYMOUS
+            
\ No newline at end of file
diff --git a/sasl_conf/proton.sasldb b/sasl_conf/proton.sasldb
new file mode 100644
index 000000000..d6a270e35
Binary files /dev/null and b/sasl_conf/proton.sasldb differ