diff --git a/include/wsrep/client_service.hpp b/include/wsrep/client_service.hpp
index b4d8abd..ac29e37 100644
--- a/include/wsrep/client_service.hpp
+++ b/include/wsrep/client_service.hpp
@@ -180,15 +180,6 @@ namespace wsrep
          */
         virtual void debug_crash(const char* crash_point) = 0;
     };
-
-    /**
-     * Debug callback methods. These methods are called only in
-     * builds that have WITH_DEBUG defined.
-     */
-    class client_debug_callback
-    {
-    public:
-    };
 }
 
 #endif // WSREP_CLIENT_SERVICE_HPP
diff --git a/include/wsrep/client_state.hpp b/include/wsrep/client_state.hpp
index ac28df6..f675c9d 100644
--- a/include/wsrep/client_state.hpp
+++ b/include/wsrep/client_state.hpp
@@ -987,7 +987,6 @@ namespace wsrep
 
         friend class client_state_switch;
         friend class high_priority_context;
-        friend class client_toi_mode;
         friend class transaction;
 
         void do_acquire_ownership(wsrep::unique_lock<wsrep::mutex>& lock);
@@ -1122,31 +1121,6 @@ namespace wsrep
         wsrep::client_state& client_;
         enum wsrep::client_state::mode orig_mode_;
     };
-
-    /**
-     *
-     */
-    class client_toi_mode
-    {
-    public:
-        client_toi_mode(wsrep::client_state& client)
-            : client_(client)
-            , orig_mode_(client.mode_)
-        {
-            wsrep::unique_lock<wsrep::mutex> lock(client.mutex_);
-            client.mode(lock, wsrep::client_state::m_toi);
-        }
-        ~client_toi_mode()
-        {
-            wsrep::unique_lock<wsrep::mutex> lock(client_.mutex_);
-            assert(client_.mode() == wsrep::client_state::m_toi);
-            client_.mode(lock, orig_mode_);
-        }
-    private:
-        wsrep::client_state& client_;
-        enum wsrep::client_state::mode orig_mode_;
-    };
-
 }
 
 #endif // WSREP_CLIENT_STATE_HPP
diff --git a/src/applier.hpp b/src/applier.hpp
deleted file mode 100644
index 9e2bc81..0000000
--- a/src/applier.hpp
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright (C) 2018 Codership Oy <info@codership.com>
- *
- * This file is part of wsrep-lib.
- *
- * Wsrep-lib is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * Wsrep-lib is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with wsrep-lib.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-#ifndef WSREP_APPLIER_HPP
-#define WSREP_APPLIER_HPP
-
-namespace wsrep
-{
-    class applier
-    {
-
-    };
-}
-
-#endif // WSREP_APPLIER_HPP