diff --git a/src/Adapter.cc b/src/Adapter.cc
index 23cd2fe..30fe078 100644
--- a/src/Adapter.cc
+++ b/src/Adapter.cc
@@ -207,14 +207,23 @@ namespace pEp {
             _inject_sync_event(nullptr, nullptr);
         }
 
+        void start_sync()
+        {
+            startup<pEp::CallbackDispatcher>(
+                &callback_dispatcher,
+                &::pEp::CallbackDispatcher::on_startup,
+                &::pEp::CallbackDispatcher::on_shutdown);
+        }
+
         // public
-        void shutdown()
+        void stop_sync()
         {
             pEpLog("called");
             if (_sync_thread.joinable()) {
                 pEpLog("sync_is_running - injecting null event");
                 inject_sync_shutdown();
                 _sync_thread.join();
+                pEp::callback_dispatcher.notifyHandshake(nullptr, nullptr, SYNC_NOTIFY_STOP);
             }
         }
 
diff --git a/src/Adapter.hh b/src/Adapter.hh
index 41c88b7..3f6f2b9 100644
--- a/src/Adapter.hh
+++ b/src/Adapter.hh
@@ -47,6 +47,8 @@ namespace pEp {
 
         ::PEP_STATUS _ensure_passphrase(::PEP_SESSION session, const char *fpr);
 
+        void start_sync();
+
         template<class T = void>
         void startup(
             messageToSend_t messageToSend,
@@ -84,7 +86,7 @@ namespace pEp {
 
         // injects a NULL event into sync_event_queue to denote sync thread to
         // shutdown, and joins & removes the sync thread
-        void shutdown();
+        void stop_sync();
 
         bool is_sync_running();
         bool in_shutdown();
diff --git a/src/callback_dispatcher.cc b/src/callback_dispatcher.cc
index 7a50dbc..5cc7491 100644
--- a/src/callback_dispatcher.cc
+++ b/src/callback_dispatcher.cc
@@ -5,6 +5,7 @@
 #include "passphrase_cache.hh"
 #include <stdexcept>
 #include <cassert>
+#include "Adapter.hh"
 
 pEp::CallbackDispatcher pEp::callback_dispatcher;
 
@@ -51,7 +52,7 @@ namespace pEp {
         }
 
         if (targets.empty()) {
-            stop_sync();
+            Adapter::stop_sync();
         }
     }
 
@@ -73,39 +74,6 @@ namespace pEp {
         }
     }
 
-    void CallbackDispatcher::start_sync()
-    {
-        pEpLog("called");
-        callback_dispatcher.semaphore.go();
-
-        pEp::Adapter::startup<CallbackDispatcher>(
-            CallbackDispatcher::messageToSend,
-            CallbackDispatcher::notifyHandshake,
-            &callback_dispatcher,
-            &CallbackDispatcher::on_startup,
-            &CallbackDispatcher::on_shutdown);
-
-        pEpLog("all targets signal: SYNC_NOTIFY_START");
-        for (auto target : callback_dispatcher.targets) {
-            if (target.notifyHandshake) {
-                target.notifyHandshake(nullptr, nullptr, SYNC_NOTIFY_START);
-            }
-        }
-    }
-
-    void CallbackDispatcher::stop_sync()
-    {
-        callback_dispatcher.semaphore.stop();
-        Adapter::shutdown();
-        callback_dispatcher.semaphore.go();
-
-        for (auto target : callback_dispatcher.targets) {
-            if (target.notifyHandshake) {
-                target.notifyHandshake(nullptr, nullptr, SYNC_NOTIFY_STOP);
-            }
-        }
-    }
-
     PEP_STATUS CallbackDispatcher::_messageToSend(::message *msg)
     {
         if (Adapter::on_sync_thread() && !msg) {
diff --git a/src/callback_dispatcher.hh b/src/callback_dispatcher.hh
index 5a75e29..8dfd272 100644
--- a/src/callback_dispatcher.hh
+++ b/src/callback_dispatcher.hh
@@ -7,10 +7,10 @@
 #include <vector>
 #include <functional>
 #include <mutex>
-#include "Adapter.hh"
+
 #include "Semaphore.hh"
 #include "passphrase_cache.hh"
-
+#include <pEp/sync_api.h>
 namespace pEp {
     // use this class when implementing a desktop adapter
     // register different interfaces with add()
@@ -37,18 +37,15 @@ namespace pEp {
             proc on_shutdown = nullptr);
         void remove(::messageToSend_t messageToSend);
 
-        static void start_sync();
-        static void stop_sync();
-
         static PEP_STATUS messageToSend(::message *msg);
         static PEP_STATUS notifyHandshake(
             ::pEp_identity *me,
             ::pEp_identity *partner,
             ::sync_handshake_signal signal);
 
-    protected:
         void on_startup();
         void on_shutdown();
+    protected:
 
         PEP_STATUS _messageToSend(::message *msg);
         PEP_STATUS _notifyHandshake(