diff --git a/CMakeLists.txt b/CMakeLists.txt
index 79a836f..07fff5a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required (VERSION 3.7)
 project (expandurl-mastodon
-         VERSION 0.2.6
+         VERSION 0.3.0
          LANGUAGES CXX
 )
 
diff --git a/src/masto.cpp b/src/masto.cpp
index 84df9c6..600f577 100644
--- a/src/masto.cpp
+++ b/src/masto.cpp
@@ -17,6 +17,7 @@
 #include <fstream>
 #include <cstdlib>  // getenv()
 #include <iostream>
+#include <mutex>
 #include "version.hpp"
 #include "expandurl-mastodon.hpp"
 
@@ -65,6 +66,10 @@ const void Listener::start()
         cout << "DEBUG: Connection lost.\n";
         _running = false;
     });
+    while (_ptr == nullptr)
+    {
+        std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    }
 }
 
 const void Listener::stop()
@@ -85,6 +90,7 @@ std::vector<Easy::Notification> Listener::get_new_messages()
     std::vector<Easy::Notification> v;
     static std::uint_fast8_t count_empty = 0;
 
+    std::lock_guard<std::mutex> lock(_ptr->get_mutex());
     if (!_stream.empty())
     {
         const string buffer = _stream;