diff --git a/src/mvlc_nng_replay.cc b/src/mvlc_nng_replay.cc
index 71ad1e4..cfbf3e1 100644
--- a/src/mvlc_nng_replay.cc
+++ b/src/mvlc_nng_replay.cc
@@ -270,61 +270,57 @@ struct __attribute__((packed, aligned(1))) ParsedModuleHeader
     u32 dynamicSize;
 };
 
-void parser_nng_eventdata_v1(void *ctx_, int crateIndex, int eventIndex,
-    const readout_parser::ModuleData *moduleDataList, unsigned moduleCount)
+static const size_t OutputMessageReserved = util::Megabytes(1);
+
+bool allocate_output_message(ParserNngContext &ctx, const char *debugInfo = "")
 {
-    assert(crateIndex >= 0 && crateIndex <= std::numeric_limits<u8>::max());
-    assert(eventIndex >= 0 && eventIndex <= std::numeric_limits<u8>::max());
-    assert(moduleCount < std::numeric_limits<u8>::max());
+    auto &msg = ctx.outputMessage;
 
-    auto &ctx = *reinterpret_cast<ParserNngContext *>(ctx_);
-    ++ctx.totalReadoutEvents;
-    auto msg = ctx.outputMessage;
+    if (msg)
+        return false;
 
-    ParsedDataEventHeader eventHeader =
+    if (auto res = nng_msg_alloc(&msg, 0))
     {
-        0xF3u,
-        static_cast<u8>(crateIndex),
-        static_cast<u8>(eventIndex),
-        static_cast<u8>(moduleCount),
+        spdlog::error("{} - nng_msg_alloc: {}", debugInfo, nng_strerror(res));
+        return false;
+    }
+
+    if (auto res = nng_msg_reserve(msg, OutputMessageReserved))
+    {
+        spdlog::error("{} - nng_msg_reserve: {}", debugInfo, nng_strerror(res));
+        return false;
+    }
+
+    ParsedEventsMessageHeader header =
+    {
+        MessageType::ParsedEvents,
+        ++ctx.outputMessageNumber,
     };
 
-    if (int res = nng_msg_append(msg, &eventHeader, sizeof(eventHeader)))
+    nng_msg_append(msg, &header, sizeof(header));
+    assert(nng_msg_len(msg) == sizeof(header));
+
+    return true;
+}
+
+bool flush_output_message(ParserNngContext &ctx, const char *debugInfo = "")
+{
+    const auto msgSize = nng_msg_len(ctx.outputMessage);
+
+    if (auto res = send_message_retry(ctx.outputSocket, ctx.outputMessage, 0, debugInfo))
     {
-        spdlog::error("parser_nng_eventdata_v1: nng_msg_append: {}", nng_strerror(res));
-        return;
+        nng_msg_free(ctx.outputMessage);
+        ctx.outputMessage = nullptr;
+        spdlog::error("{}: send_message_retry: {}:", debugInfo, nng_strerror(res));
+        return false;
     }
 
-    #if 1
-    for (size_t moduleIndex = 0; moduleIndex < moduleCount; ++moduleIndex)
-    {
-        auto &moduleData = moduleDataList[moduleIndex];
+    ctx.outputMessage = nullptr;
 
-        ParsedModuleHeader moduleHeader = {};
-        moduleHeader.prefixSize = moduleData.prefixSize;
-        moduleHeader.dynamicSize = moduleData.dynamicSize;
-        moduleHeader.suffixSize = moduleData.suffixSize;
+    spdlog::debug("{}: sent message {} of size {}",
+        debugInfo, ctx.outputMessageNumber, msgSize);
 
-        if (int res = nng_msg_append(msg, &moduleHeader, sizeof(moduleHeader)))
-        {
-            spdlog::error("parser_nng_eventdata_v1: nng_msg_append: {}", nng_strerror(res));
-            return;
-        }
-
-        auto prefixSpan = prefix_span(moduleData);
-        auto dynamicSpan = dynamic_span(moduleData);
-        auto suffixSpan = suffix_span(moduleData);
-
-        for (auto &dataSpan: { prefixSpan, dynamicSpan, suffixSpan })
-        {
-            if (int res = nng_msg_append(msg, dataSpan.data, dataSpan.size * sizeof(u32)))
-            {
-                spdlog::error("parser_nng_eventdata_v1: nng_msg_append: {}", nng_strerror(res));
-                return;
-            }
-        }
-    }
-    #endif
+    return true;
 }
 
 void parser_nng_eventdata_v2(void *ctx_, int crateIndex, int eventIndex,
@@ -334,31 +330,10 @@ void parser_nng_eventdata_v2(void *ctx_, int crateIndex, int eventIndex,
     assert(eventIndex >= 0 && eventIndex <= std::numeric_limits<u8>::max());
     assert(moduleCount < std::numeric_limits<u8>::max());
 
-    static const size_t OutputMessageReserved= util::Megabytes(1);
 
-    auto &parserContext = *reinterpret_cast<ParserNngContext *>(ctx_);
-    ++parserContext.totalReadoutEvents;
-    auto &msg = parserContext.outputMessage;
-
-    auto flush_output_message = [&]
-    {
-        const auto msgSize = nng_msg_len(parserContext.outputMessage);
-
-        if (auto res = send_message_retry(parserContext.outputSocket, parserContext.outputMessage, 0, "listfile_parser_nng"))
-        {
-            nng_msg_free(parserContext.outputMessage);
-            parserContext.outputMessage = nullptr;
-            spdlog::error("listfile_parser_nng: send_message_retry: {}:", nng_strerror(res));
-            return false;
-        }
-
-        parserContext.outputMessage = nullptr;
-
-        spdlog::debug("listfile_parser_nng: sent message {} of size {}",
-            parserContext.outputMessageNumber, msgSize);
-
-        return true;
-    };
+    auto &ctx = *reinterpret_cast<ParserNngContext *>(ctx_);
+    ++ctx.totalReadoutEvents;
+    auto &msg = ctx.outputMessage;
 
     size_t requiredBytes = sizeof(ParsedDataEventHeader);
 
@@ -373,33 +348,12 @@ void parser_nng_eventdata_v2(void *ctx_, int crateIndex, int eventIndex,
 
     if (msg && bytesFree < requiredBytes)
     {
-        if (!flush_output_message())
+        if (!flush_output_message(ctx, "parser_nng_eventdata_v2"))
             return;
     }
 
-    if (!msg)
-    {
-        if (auto res = nng_msg_alloc(&msg, 0))
-        {
-            spdlog::error("listfile_parser_nng - nng_msg_alloc: {}", nng_strerror(res));
-            return;
-        }
-
-        if (auto res = nng_msg_reserve(msg, OutputMessageReserved))
-        {
-            spdlog::error("listfile_parser_nng - nng_msg_reserve: {}", nng_strerror(res));
-            return;
-        }
-
-        ParsedEventsMessageHeader header =
-        {
-            MessageType::ParsedEvents,
-            ++parserContext.outputMessageNumber,
-        };
-
-        nng_msg_append(msg, &header, sizeof(header));
-        assert(nng_msg_len(msg) == sizeof(header));
-    }
+    if (!msg && !allocate_output_message(ctx, "parser_nng_eventdata_v2"))
+        return;
 
     bytesFree =  msg ? OutputMessageReserved - nng_msg_len(msg) : 0u;
     assert(bytesFree >= requiredBytes);
@@ -414,11 +368,10 @@ void parser_nng_eventdata_v2(void *ctx_, int crateIndex, int eventIndex,
 
     if (int res = nng_msg_append(msg, &eventHeader, sizeof(eventHeader)))
     {
-        spdlog::error("parser_nng_eventdata_v1: nng_msg_append: {}", nng_strerror(res));
+        spdlog::error("parser_nng_eventdata_v2: nng_msg_append: {}", nng_strerror(res));
         return;
     }
 
-    #if 1
     for (size_t moduleIndex = 0; moduleIndex < moduleCount; ++moduleIndex)
     {
         auto &moduleData = moduleDataList[moduleIndex];
@@ -430,27 +383,39 @@ void parser_nng_eventdata_v2(void *ctx_, int crateIndex, int eventIndex,
 
         if (int res = nng_msg_append(msg, &moduleHeader, sizeof(moduleHeader)))
         {
-            spdlog::error("parser_nng_eventdata_v1: nng_msg_append: {}", nng_strerror(res));
+            spdlog::error("parser_nng_eventdata_v2: nng_msg_append: {}", nng_strerror(res));
             return;
         }
 
         if (int res = nng_msg_append(msg, moduleData.data.data, moduleData.data.size * sizeof(u32)))
         {
-            spdlog::error("parser_nng_eventdata_v1: nng_msg_append: {}", nng_strerror(res));
+            spdlog::error("parser_nng_eventdata_v2: nng_msg_append: {}", nng_strerror(res));
             return;
         }
     }
-    #endif
 }
 
-void parser_nng_systemevent(void *ctx_, int crateIndex, const u32 *header, u32 size)
+void parser_nng_systemevent_v2(void *ctx_, int crateIndex, const u32 *header, u32 size)
 {
     assert(crateIndex >= 0 && crateIndex <= std::numeric_limits<u8>::max());
-
     auto &ctx = *reinterpret_cast<ParserNngContext *>(ctx_);
     ++ctx.totalSystemEvents;
+    auto &msg = ctx.outputMessage;
 
-    auto msg = ctx.outputMessage;
+    size_t requiredBytes = sizeof(ParsedSystemEventHeader) + size * sizeof(u32);
+    size_t bytesFree =  msg ? OutputMessageReserved - nng_msg_len(msg) : 0u;
+
+    if (msg && bytesFree < requiredBytes)
+    {
+        if (!flush_output_message(ctx, "parser_nng_systemevent_v2"))
+            return;
+    }
+
+    if (!msg && !allocate_output_message(ctx, "parser_nng_systemevent_v2"))
+        return;
+
+    bytesFree =  msg ? OutputMessageReserved - nng_msg_len(msg) : 0u;
+    assert(bytesFree >= requiredBytes);
 
     ParsedSystemEventHeader eventHeader =
     {
@@ -465,7 +430,6 @@ void parser_nng_systemevent(void *ctx_, int crateIndex, const u32 *header, u32 s
         return;
     }
 
-
     if (int res = nng_msg_append(msg, header, size * sizeof(u32)))
     {
         spdlog::error("parser_nng_systemevent: nng_msg_append: {}", nng_strerror(res));
@@ -543,7 +507,7 @@ void listfile_parser_nng(
     mvlc::readout_parser::ReadoutParserCallbacks parserCallbacks =
     {
         parser_nng_eventdata_v2,
-        parser_nng_systemevent,
+        parser_nng_systemevent_v2,
     };
 
     nng_msg *inputMsg = nullptr;
@@ -614,22 +578,6 @@ void listfile_parser_nng(
             auto inputData = reinterpret_cast<const u32 *>(nng_msg_body(inputMsg));
             size_t inputLen = nng_msg_len(inputMsg) / sizeof(u32);
 
-            if (!parserContext.outputMessage)
-            {
-                if (auto res = nng_msg_alloc(&parserContext.outputMessage, nng_msg_len(inputMsg) * 1.5))
-                {
-                    spdlog::error("listfile_parser_nng - nng_msg_alloc: {}", nng_strerror(res));
-                    break;
-                }
-
-                auto &outputHeader = *reinterpret_cast<ParsedEventsMessageHeader *>(nng_msg_body(parserContext.outputMessage));
-                outputHeader.messageType = MessageType::ParsedEvents;
-                outputHeader.messageNumber = ++outputMessageNumber;
-                nng_msg_realloc(parserContext.outputMessage, sizeof(ParsedEventsMessageHeader));
-            }
-
-            assert(parserContext.outputMessage);
-
             readout_parser::parse_readout_buffer(
                 listfileFormat,
                 parserState,
@@ -642,27 +590,6 @@ void listfile_parser_nng(
             tProcess += stopWatch.interval();
 
             // TODO: also flush after a certain time
-            #if 0
-            if (nng_msg_len(parserContext.outputMessage) >= util::Megabytes(1))
-            {
-                const auto msgSize = nng_msg_len(parserContext.outputMessage);
-
-                if (auto res = send_message_retry(outputSocket, parserContext.outputMessage, 0, "listfile_parser_nng"))
-                {
-                    nng_msg_free(parserContext.outputMessage);
-                    parserContext.outputMessage = nullptr;
-                    spdlog::error("listfile_parser_nng: send_message_retry: {}:", nng_strerror(res));
-                    break;
-                }
-
-                parserContext.outputMessage = nullptr;
-
-                spdlog::debug("listfile_parser_nng: sent message {} of size {}",
-                    outputMessageNumber, msgSize);
-            }
-
-            tSend += stopWatch.interval();
-            #endif
             tTotal += stopWatch.end();
         }
 
@@ -686,21 +613,7 @@ void listfile_parser_nng(
     }
 
     if (parserContext.outputMessage)
-    {
-        const auto msgSize = nng_msg_len(parserContext.outputMessage);
-
-        if (auto res = send_message_retry(outputSocket, parserContext.outputMessage, 0, "listfile_parser_nng"))
-        {
-            nng_msg_free(parserContext.outputMessage);
-            parserContext.outputMessage = nullptr;
-            spdlog::error("listfile_parser_nng: send_message_retry: {}:", nng_strerror(res));
-        }
-
-        parserContext.outputMessage = nullptr;
-
-        spdlog::debug("listfile_parser_nng: sent message {} of size {}",
-            outputMessageNumber, msgSize);
-    }
+        flush_output_message(parserContext, "listfile_parser_nng_v2");
 
     if (inputMsg)
     {
@@ -844,4 +757,4 @@ int main(int argc, char *argv[])
     }
 
     return 0;
-}
\ No newline at end of file
+}