diff --git a/c_src/mongoose_mam_id.cpp b/c_src/mongoose_mam_id.cpp
deleted file mode 100644
index 0a0f06e8900..00000000000
--- a/c_src/mongoose_mam_id.cpp
+++ /dev/null
@@ -1,48 +0,0 @@
-/**
- * @file mongoose_mam_id.cpp
- * @author konrad.zemek@erlang-solutions.com
- * @copyright 2017 Erlang Solutions Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <erl_nif.h>
-
-#include <atomic>
-#include <cstdint>
-
-static std::atomic<std::uint_fast64_t> counter{ 0 };
-
-extern "C" {
-static ERL_NIF_TERM next_unique(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
-{
-    ErlNifUInt64 given_candidate;
-    if (!enif_get_uint64(env, argv[0], &given_candidate))
-        return enif_make_badarg(env);
-
-    std::uint_fast64_t candidate = static_cast<std::uint_fast64_t>(given_candidate);
-    std::uint_fast64_t current = candidate - 1;
-
-    while (!counter.compare_exchange_weak(current, candidate, std::memory_order_relaxed))
-        {
-            if (current >= candidate)
-                candidate = current + 1;
-        }
-
-    return enif_make_uint64(env, candidate);
-}
-
-static ErlNifFunc nif_funcs[] = { { "next_unique", 1, next_unique } };
-
-ERL_NIF_INIT(mongoose_mam_id, nif_funcs, nullptr, nullptr, nullptr, nullptr)
-}
diff --git a/rebar.config b/rebar.config
index 1f8df9254af..36ffed1f17f 100644
--- a/rebar.config
+++ b/rebar.config
@@ -37,11 +37,6 @@
     {httpd_util, integer_to_hexlist, 1}
 ]}.
 
-{port_specs,
- [
-  {".*", "priv/lib/mongoose_mam_id.so", ["c_src/mongoose_mam_id.cpp"], [{env, [{"CXXFLAGS", "$CXXFLAGS -O3 -std=c++11"}]}]}
- ]}.
-
 {require_min_otp_vsn, "21"}.
 
 %% We agreed to use https:// for deps because of possible firewall issues.
diff --git a/src/ejabberd.erl b/src/ejabberd.erl
index 1401c1fe338..284943661c3 100644
--- a/src/ejabberd.erl
+++ b/src/ejabberd.erl
@@ -25,9 +25,7 @@
 
 -module(ejabberd).
 -author('alexey@process-one.net').
--export([get_pid_file/0,
-         get_status_file/0,
-         get_so_path/0]).
+-export([get_pid_file/0, get_status_file/0]).
 
 -type lang() :: binary().
 
@@ -41,20 +39,6 @@
 
 -export_type([lang/0, xml_stream_item/0]).
 
--spec get_so_path() -> binary() | string().
-get_so_path() ->
-    case os:getenv("EJABBERD_SO_PATH") of
-        false ->
-            case code:priv_dir(mongooseim) of
-                {error, _} ->
-                    ".";
-                Path ->
-                    filename:join([Path, "lib"])
-            end;
-        Path ->
-            Path
-    end.
-
 -spec get_pid_file() -> 'false' | nonempty_string().
 get_pid_file() ->
     case os:getenv("EJABBERD_PID_PATH") of
diff --git a/src/mam/mongoose_mam_id.erl b/src/mam/mongoose_mam_id.erl
index 525e304aee4..092976d920c 100644
--- a/src/mam/mongoose_mam_id.erl
+++ b/src/mam/mongoose_mam_id.erl
@@ -20,9 +20,28 @@
 -export([next_unique/1]).
 -on_load(load/0).
 
+-spec load() -> ok.
 load() ->
-    Path = filename:join(ejabberd:get_so_path(), ?MODULE_STRING),
-    erlang:load_nif(Path, 0).
+    case persistent_term:get(?MODULE, undefined) of
+        undefined ->
+            Atomic = atomics:new(1, [{signed, false}]),
+            persistent_term:put(?MODULE, Atomic);
+        _ ->
+            ok
+    end.
 
-next_unique(_Candidate) ->
-    erlang:nif_error(not_loaded).
+-spec next_unique(integer()) -> integer().
+next_unique(Candidate) when is_integer(Candidate), 0 < Candidate ->
+    Atomic = persistent_term:get(?MODULE),
+    next_unique(Candidate, Candidate - 1, Atomic).
+
+-spec next_unique(integer(), integer(), atomics:atomics_ref()) -> integer().
+next_unique(Candidate, Current, Atomic) ->
+    case atomics:compare_exchange(Atomic, 1, Current, Candidate) of
+        Int when is_integer(Int), Candidate =< Int ->
+            next_unique(Int + 1, Int, Atomic);
+        Int when is_integer(Int) ->
+            next_unique(Candidate, Int, Atomic);
+        ok ->
+            Candidate
+    end.