diff --git a/src/network/lan.cpp b/src/network/lan.cpp
index 80b4c9671..7762edfde 100644
--- a/src/network/lan.cpp
+++ b/src/network/lan.cpp
@@ -30,9 +30,10 @@ along with Freeminer.  If not, see <http://www.gnu.org/licenses/>.
 #include "server/serverlist.h"
 #include "debug.h"
 #include "json/json.h"
+#include <mutex>
+#include <shared_mutex>
 #include "porting.h"
 #include "threading/thread.h"
-#include "threading/concurrent_map.h"
 #include "network/address.h"
 
 //copypaste from ../socket.cpp
@@ -303,6 +304,7 @@ void *lan_adv::run()
 			if (p["port"].isInt()) {
 				p["address"] = addr_str;
 				auto key = addr_str + ":" + p["port"].asString();
+				std::unique_lock lock(mutex);
 				if (p["cmd"].asString() == "shutdown") {
 					//infostream << "server shutdown " << key << "\n";
 					collected.erase(key);
diff --git a/src/network/lan.h b/src/network/lan.h
index ea058f1ae..085a597a2 100644
--- a/src/network/lan.h
+++ b/src/network/lan.h
@@ -20,10 +20,11 @@ along with Freeminer.  If not, see <http://www.gnu.org/licenses/>.
 #pragma once
 
 #include "json/json.h"
+#include <map>
+#include <shared_mutex>
 #include <string>
 #include <atomic>
 #include "threading/thread.h"
-#include "threading/concurrent_map.h"
 
 
 class lan_adv : public Thread
@@ -37,7 +38,9 @@ public:
 
 	void serve(unsigned short port);
 
-	concurrent_map<std::string, Json::Value> collected;
+	std::map<std::string, Json::Value> collected;
+	std::shared_mutex mutex;
+
 	std::atomic_bool fresh;
 	std::atomic_int clients_num;
 
diff --git a/src/script/lua_api/l_mainmenu.cpp b/src/script/lua_api/l_mainmenu.cpp
index 6a637f7d7..f7ba929cc 100644
--- a/src/script/lua_api/l_mainmenu.cpp
+++ b/src/script/lua_api/l_mainmenu.cpp
@@ -1101,6 +1101,7 @@ int ModApiMainMenu::l_get_lan_servers(lua_State *L)
 	int top = lua_gettop(L);
 	unsigned int index = 1;
 
+	std::shared_lock lock(ServerList::lan_adv_client.mutex);
 	for (const auto &server : ServerList::lan_adv_client.collected) {
 		lua_pushnumber(L, index);
 
diff --git a/src/threading/concurrent_map.h b/src/threading/concurrent_map.h
deleted file mode 100644
index c07971d59..000000000
--- a/src/threading/concurrent_map.h
+++ /dev/null
@@ -1,209 +0,0 @@
-/*
-Copyright (C) 2024 proller <proler@gmail.com>
-*/
-
-/*
-This file is part of Freeminer.
-
-Freeminer 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 3 of the License, or
-(at your option) any later version.
-
-Freeminer  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 Freeminer.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#pragma once
-
-#include <map>
-
-#include "lock.h"
-
-template <class LOCKER, class Key, class T, class Compare = std::less<Key>,
-		class Allocator = std::allocator<std::pair<const Key, T>>>
-class concurrent_map_ : public std::map<Key, T, Compare, Allocator>, public LOCKER
-{
-public:
-	typedef typename std::map<Key, T, Compare, Allocator> full_type;
-	typedef Key key_type;
-	typedef T mapped_type;
-
-	mapped_type &operator[](const key_type &k) = delete;
-	mapped_type &operator[](key_type &&k) = delete;
-
-	mapped_type nothing = {};
-
-	template <typename... Args>
-	mapped_type& get(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-
-		//if (!full_type::contains(std::forward<Args>(args)...))
-		if (full_type::find(std::forward<Args>(args)...) == full_type::end())
-			return nothing;
-
-		return full_type::operator[](std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) at(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::at(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) assign(Args &&...args)
-	{
-		auto lock = LOCKER::lock_unique_rec();
-		return full_type::assign(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) insert(Args &&...args)
-	{
-		auto lock = LOCKER::lock_unique_rec();
-		return full_type::insert(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) emplace(Args &&...args)
-	{
-		auto lock = LOCKER::lock_unique_rec();
-		return full_type::emplace(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) emplace_try(Args &&...args)
-	{
-		auto lock = LOCKER::try_lock_unique_rec();
-		if (!lock->owns_lock())
-			return false;
-		return full_type::emplace(std::forward<Args>(args)...).second;
-	}
-
-	template <typename... Args>
-	decltype(auto) insert_or_assign(Args &&...args)
-	{
-		auto lock = LOCKER::lock_unique_rec();
-		return full_type::insert_or_assign(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) empty(Args &&...args) const noexcept
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::empty(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) size(Args &&...args) const
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::size(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) count(Args &&...args) const
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::count(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) contains(Args &&...args) const
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::contains(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) find(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::find(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) begin(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::begin(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) rbegin(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::rbegin(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) end(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::end(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) rend(Args &&...args)
-	{
-		auto lock = LOCKER::lock_shared_rec();
-		return full_type::rend(std::forward<Args>(args)...);
-	}
-
-
-	template <typename... Args>
-	decltype(auto) erase(Args &&...args)
-	{
-		auto lock = LOCKER::lock_unique_rec();
-		return full_type::erase(std::forward<Args>(args)...);
-	}
-
-	template <typename... Args>
-	decltype(auto) clear(Args &&...args)
-	{
-		auto lock = LOCKER::lock_unique_rec();
-		return full_type::clear(std::forward<Args>(args)...);
-	}
-};
-
-template <class Key, class T, class Compare = std::less<Key>,
-		class Allocator = std::allocator<std::pair<const Key, T>>>
-using concurrent_map = concurrent_map_<locker<>, Key, T, Compare, Allocator>;
-
-template <class Key, class T, class Compare = std::less<Key>, class Allocator = std::allocator<std::pair<const Key, T>>>
-using concurrent_shared_map = concurrent_map_<shared_locker, Key, T, Compare, Allocator>;
-
-#if ENABLE_THREADS
-
-template <class Key, class T, class Compare = std::less<Key>,
-		class Allocator = std::allocator<std::pair<const Key, T>>>
-using maybe_concurrent_map = concurrent_map<Key, T, Compare, Allocator>;
-
-#else
-
-template <class Key, class T, class Compare = std::less<Key>,
-		class Allocator = std::allocator<std::pair<const Key, T>>>
-class not_concurrent_map : public std::map<Key, T, Compare, Allocator>,
-						   public dummy_locker
-{
-public:
-	typedef typename std::map<Key, T, Compare, Allocator> full_type;
-	typedef Key key_type;
-	typedef T mapped_type;
-
-	mapped_type &get(const key_type &k) { return full_type::operator[](k); }
-};
-
-template <class Key, class T, class Compare = std::less<Key>,
-		class Allocator = std::allocator<std::pair<const Key, T>>>
-using maybe_concurrent_map = not_concurrent_map<Key, T, Compare, Allocator>;
-
-#endif
\ No newline at end of file
diff --git a/src/threading/lock.cpp b/src/threading/lock.cpp
deleted file mode 100644
index d80055447..000000000
--- a/src/threading/lock.cpp
+++ /dev/null
@@ -1,131 +0,0 @@
-#include "lock.h"
-#include "log.h"
-#include "profiler.h"
-
-#if !defined(NDEBUG) && !defined(LOCK_PROFILE)
-//#define LOCK_PROFILE 1
-#endif
-
-#if LOCK_PROFILE
-#define SCOPE_PROFILE(a) ScopeProfiler scp___(g_profiler, "Lock: " a);
-#else
-#define SCOPE_PROFILE(a)
-#endif
-
-template<class GUARD, class MUTEX>
-recursive_lock<GUARD, MUTEX>::recursive_lock(MUTEX & mtx, std::atomic<std::size_t> & thread_id_, bool try_lock):
-	thread_id(thread_id_) {
-	auto thread_me = std::hash<std::thread::id>()(std::this_thread::get_id());
-	if(thread_me != thread_id) {
-		if (try_lock) {
-			SCOPE_PROFILE("try_lock");
-			lock = new GUARD(mtx, try_to_lock);
-			if (lock->owns_lock()) {
-				thread_id = thread_me;
-				return;
-			} else {
-#if LOCK_PROFILE
-				g_profiler->add("Lock: try_lock fail", 1);
-#endif
-				//infostream<<"not locked "<<" thread="<<thread_id<<" lock="<<lock<<std::endl;
-			}
-			delete lock;
-		} else {
-			SCOPE_PROFILE("lock");
-			lock = new GUARD(mtx);
-			thread_id = thread_me;
-			return;
-		}
-	} else {
-#if LOCK_PROFILE
-		g_profiler->add("Lock: recursive", 1);
-#endif
-	}
-	lock = nullptr;
-}
-
-template<class GUARD, class MUTEX>
-recursive_lock<GUARD, MUTEX>::~recursive_lock() {
-	unlock();
-}
-
-template<class GUARD, class MUTEX>
-bool recursive_lock<GUARD, MUTEX>::owns_lock() {
-	if (lock)
-		return lock;
-	auto thread_me = std::hash<std::thread::id>()(std::this_thread::get_id());
-	return thread_id == thread_me;
-}
-
-template<class GUARD, class MUTEX>
-void recursive_lock<GUARD, MUTEX>::unlock() {
-	if(lock) {
-		thread_id = 0;
-		lock->unlock();
-		delete lock;
-		lock = nullptr;
-	}
-}
-
-
-template<class mutex, class unique_lock, class shared_lock>
-locker<mutex, unique_lock, shared_lock>::locker() {
-	thread_id = 0;
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<unique_lock> locker<mutex, unique_lock, shared_lock>::lock_unique() {
-	return std::make_unique<unique_lock>(mtx);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<unique_lock> locker<mutex, unique_lock, shared_lock>::try_lock_unique() {
-	SCOPE_PROFILE("locker::try_lock_unique");
-	return std::make_unique<unique_lock>(mtx, std::try_to_lock);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<shared_lock> locker<mutex, unique_lock, shared_lock>::lock_shared() const {
-	SCOPE_PROFILE("locker::lock_shared");
-	return std::make_unique<shared_lock>(mtx);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<shared_lock> locker<mutex, unique_lock, shared_lock>::try_lock_shared() {
-	SCOPE_PROFILE("locker::try_lock_shared");
-	return std::make_unique<shared_lock>(mtx, std::try_to_lock);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<recursive_lock<unique_lock, mutex>> locker<mutex, unique_lock, shared_lock>::lock_unique_rec() const {
-	SCOPE_PROFILE("locker::lock_unique_rec");
-	return std::make_unique<lock_rec_unique>(mtx, thread_id);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<recursive_lock<unique_lock, mutex>> locker<mutex, unique_lock, shared_lock>::try_lock_unique_rec() {
-	SCOPE_PROFILE("locker::try_lock_unique_rec");
-	return std::make_unique<lock_rec_unique>(mtx, thread_id, true);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<recursive_lock<shared_lock, mutex>> locker<mutex, unique_lock, shared_lock>::lock_shared_rec() const {
-	SCOPE_PROFILE("locker::lock_shared_rec");
-	return std::make_unique<lock_rec_shared>(mtx, thread_id);
-}
-
-template<class mutex, class unique_lock, class shared_lock>
-std::unique_ptr<recursive_lock<shared_lock, mutex>> locker<mutex, unique_lock, shared_lock>::try_lock_shared_rec() {
-	SCOPE_PROFILE("locker::try_lock_shared_rec");
-	return std::make_unique<lock_rec_shared>(mtx, thread_id, true);
-}
-
-
-template class recursive_lock<std::unique_lock<use_mutex>>;
-template class locker<>;
-#if LOCK_TWO
-template class recursive_lock<try_shared_lock, try_shared_mutex>;
-template class recursive_lock<std::unique_lock<try_shared_mutex>, try_shared_mutex>;
-
-template class locker<try_shared_mutex, std::unique_lock<try_shared_mutex>, std::shared_lock<try_shared_mutex>>;
-#endif
\ No newline at end of file
diff --git a/src/threading/lock.h b/src/threading/lock.h
deleted file mode 100644
index a3cd43e29..000000000
--- a/src/threading/lock.h
+++ /dev/null
@@ -1,164 +0,0 @@
-/*
-This file is part of Freeminer.
-
-Freeminer 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 3 of the License, or
-(at your option) any later version.
-
-Freeminer  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 Freeminer.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#pragma once
-
-#include <mutex>
-#include <atomic>
-#include <thread>
-#include <memory>
-
-#include "../config.h"
-
-#ifdef _WIN32
-
-//#include "../threading/mutex.h"
-using use_mutex = std::mutex;
-using try_shared_mutex = use_mutex;
-using try_shared_lock = std::unique_lock<try_shared_mutex>;
-using unique_lock = std::unique_lock<try_shared_mutex>;
-const auto try_to_lock = std::try_to_lock;
-
-#else
-
-typedef std::mutex use_mutex;
-
-
-#if USE_BOOST // not finished
-
-//#include <ctime>
-#include <boost/thread.hpp>
-//#include <boost/thread/locks.hpp>
-typedef boost::shared_mutex try_shared_mutex;
-typedef boost::shared_lock<try_shared_mutex> try_shared_lock;
-typedef boost::unique_lock<try_shared_mutex> unique_lock;
-const auto try_to_lock = boost::try_to_lock;
-#define LOCK_TWO 1
-
-#elif HAVE_SHARED_MUTEX
-//#elif __cplusplus >= 201305L
-
-#include <shared_mutex>
-using try_shared_mutex = std::shared_mutex;
-using try_shared_lock = std::shared_lock<try_shared_mutex>;
-using unique_lock = std::unique_lock<try_shared_mutex>;
-const auto try_to_lock = std::try_to_lock;
-#define LOCK_TWO 1
-
-#else
-
-using try_shared_mutex = use_mutex;
-using try_shared_lock = std::unique_lock<try_shared_mutex> ;
-using unique_lock = std::unique_lock<try_shared_mutex> ;
-const auto try_to_lock = std::try_to_lock;
-#endif
-
-#endif
-
-
-// http://stackoverflow.com/questions/4792449/c0x-has-no-semaphores-how-to-synchronize-threads
-/* uncomment when need
-#include <condition_variable>
-class semaphore {
-private:
-	std::mutex mtx;
-	std::condition_variable cv;
-	int count;
-
-public:
-	semaphore(int count_ = 0):count(count_){;}
-	void notify() {
-	std::unique_lock<std::mutex> lck(mtx);
-		++count;
-		cv.notify_one();
-	}
-	void wait() {
-		std::unique_lock<std::mutex> lck(mtx);
-		while(count == 0){
-			cv.wait(lck);
-		}
-		count--;
-	}
-};
-*/
-
-template<class GUARD, class MUTEX = use_mutex>
-class recursive_lock {
-public:
-	GUARD * lock;
-	std::atomic<std::size_t> & thread_id;
-	recursive_lock(MUTEX & mtx, std::atomic<std::size_t> & thread_id_, bool try_lock = false);
-	~recursive_lock();
-	bool owns_lock();
-	void unlock();
-};
-
-template<class mutex = use_mutex, class unique_lock = std::unique_lock<mutex> , class shared_lock = std::unique_lock<mutex> >
-class locker {
-public:
-	using lock_rec_shared = recursive_lock<shared_lock, mutex>;
-	using lock_rec_unique = recursive_lock<unique_lock, mutex>;
-
-	mutable mutex mtx;
-	mutable std::atomic<std::size_t> thread_id;
-
-	locker();
-	std::unique_ptr<unique_lock> lock_unique();
-	std::unique_ptr<unique_lock> try_lock_unique();
-	std::unique_ptr<shared_lock> lock_shared() const;
-	std::unique_ptr<shared_lock> try_lock_shared();
-	std::unique_ptr<lock_rec_unique> lock_unique_rec() const;
-	std::unique_ptr<lock_rec_unique> try_lock_unique_rec();
-	std::unique_ptr<lock_rec_shared> lock_shared_rec() const;
-	std::unique_ptr<lock_rec_shared> try_lock_shared_rec();
-};
-
-using shared_locker = locker<try_shared_mutex, unique_lock, try_shared_lock>;
-
-class dummy_lock {
-public:
-	~dummy_lock() {}; //no unused variable warning
-	bool owns_lock() {return true;}
-	bool operator!() {return true;}
-	dummy_lock * operator->() {return this; }
-	void unlock() {};
-};
-
-class dummy_locker {
-public:
-	dummy_lock lock_unique() { return {}; };
-	dummy_lock try_lock_unique() { return {}; };
-	dummy_lock lock_shared() { return {}; };
-	dummy_lock try_lock_shared() { return {}; };
-	dummy_lock lock_unique_rec() { return {}; };
-	dummy_lock try_lock_unique_rec() { return {}; };
-	dummy_lock lock_shared_rec() { return {}; };
-	dummy_lock try_lock_shared_rec() { return {}; };
-};
-
-
-#if ENABLE_THREADS
-
-using maybe_locker = locker<>;
-using maybe_shared_locker = shared_locker;
-
-#else
-
-using maybe_locker = dummy_locker;
-using maybe_shared_locker = dummy_locker;
-
-#endif
\ No newline at end of file