diff --git a/ddsrecorder_yaml/src/cpp/recorder/YamlReaderConfiguration.cpp b/ddsrecorder_yaml/src/cpp/recorder/YamlReaderConfiguration.cpp
index 3508a46cd..fb9640fea 100644
--- a/ddsrecorder_yaml/src/cpp/recorder/YamlReaderConfiguration.cpp
+++ b/ddsrecorder_yaml/src/cpp/recorder/YamlReaderConfiguration.cpp
@@ -68,7 +68,7 @@ void RecorderConfiguration::load_ddsrecorder_configuration_(
         // Create Simple Participant Configuration
         simple_configuration = std::make_shared<SimpleParticipantConfiguration>();
         simple_configuration->id = "SimpleRecorderParticipant";
-        simple_configuration->app_id = "DDS RECORDER";
+        simple_configuration->app_id = "DDS_RECORDER";
         simple_configuration->app_metadata = "";
         simple_configuration->is_repeater = false;
 
@@ -76,7 +76,8 @@ void RecorderConfiguration::load_ddsrecorder_configuration_(
         // Create Recorder Participant Configuration
         recorder_configuration = std::make_shared<ParticipantConfiguration>();
         recorder_configuration->id = "RecorderRecorderParticipant";
-        recorder_configuration->app_id = "DDS RECORDER";
+        recorder_configuration->app_id = "DDS_RECORDER";
+        // TODO: fill metadata field once its content has been defined.
         recorder_configuration->app_metadata = "";
         recorder_configuration->is_repeater = false;
 
diff --git a/ddsrecorder_yaml/src/cpp/replayer/YamlReaderConfiguration.cpp b/ddsrecorder_yaml/src/cpp/replayer/YamlReaderConfiguration.cpp
index 40c877299..ca7ed138d 100644
--- a/ddsrecorder_yaml/src/cpp/replayer/YamlReaderConfiguration.cpp
+++ b/ddsrecorder_yaml/src/cpp/replayer/YamlReaderConfiguration.cpp
@@ -89,7 +89,7 @@ void ReplayerConfiguration::load_ddsreplayer_configuration_(
         // WARNING: Replayer configuration must have been parsed beforehand
         mcap_reader_configuration = std::make_shared<McapReaderParticipantConfiguration>();
         mcap_reader_configuration->id = "McapReaderParticipant";
-        mcap_reader_configuration->app_id = "DDS REPLAYER";
+        mcap_reader_configuration->app_id = "DDS_REPLAYER";
         mcap_reader_configuration->app_metadata = "";
         mcap_reader_configuration->is_repeater = false;
         mcap_reader_configuration->begin_time = begin_time;
@@ -101,7 +101,8 @@ void ReplayerConfiguration::load_ddsreplayer_configuration_(
         // Create Replayer Participant Configuration
         replayer_configuration = std::make_shared<SimpleParticipantConfiguration>();
         replayer_configuration->id = "ReplayerParticipant";
-        replayer_configuration->app_id = "DDS REPLAYER";
+        replayer_configuration->app_id = "DDS_REPLAYER";
+        // TODO: fill metadata field once its content has been defined.
         replayer_configuration->app_metadata = "";
         replayer_configuration->is_repeater = false;
 
diff --git a/docs/rst/notes/forthcoming_version.rst b/docs/rst/notes/forthcoming_version.rst
index 28a2ba69b..28969ab43 100644
--- a/docs/rst/notes/forthcoming_version.rst
+++ b/docs/rst/notes/forthcoming_version.rst
@@ -15,7 +15,7 @@ Next release will include the following **DDS Recorder & Replay internal adjustm
 * Store *DDS Record & Replay* version in metadata record of the generated MCAP files.
 * Move dynamic types storage from metadata to attachments MCAP section.
 * Store schemas in OMG IDL format (instead of ROS 2 msg).
-* Store `app_id` and `app_metadata` attributes in  *DDS Record & Replay* participants.
+* Set `app_id` and `app_metadata` attributes on  *DDS Record & Replay* participants.
 
 .. warning::