diff --git a/protobuf_definitions/message_formats.proto b/protobuf_definitions/message_formats.proto
index 85ed4f57..e18163ee 100644
--- a/protobuf_definitions/message_formats.proto
+++ b/protobuf_definitions/message_formats.proto
@@ -799,14 +799,14 @@ enum Resolution {
   RESOLUTION_VGA_480P = 4; // VGA (640x480).
   RESOLUTION_HD_720P = 2; // 720p HD (1280x720).
   RESOLUTION_FULLHD_1080P = 1; // 1080p Full HD (1920x1080).
-  RESOLUTION_UHD_4K = 3; // 4K Ultra HD (3840x2160).
+  RESOLUTION_UHD_4K = 3; // 4K Ultra HD (3840x2160, Only supported on X3 Ultra).
 }
 
 // Available camera frame rates.
 enum Framerate {
   FRAMERATE_UNSPECIFIED = 0; // Framerate not specified.
   FRAMERATE_FPS_30 = 1; // 30 frames per second.
-  FRAMERATE_FPS_25 = 2; // 25 frames per second.
+  FRAMERATE_FPS_25 = 2; // 25 frames per second. (Only supported on Pioneer/Pro/X1/X3)
 }
 
 // Which camera to control.
@@ -819,11 +819,12 @@ enum Camera {
 enum StreamingProtocol {
   STREAMING_PROTOCOL_UNSPECIFIED = 0; // Streaming protocol not specified.
   STREAMING_PROTOCOL_RTSP_H264 = 1; // RTSP streaming protocol using H264 codec.
-  STREAMING_PROTOCOL_RTSP_MJPEG = 2; // RTSP streaming protocol using MJPEG codec.
+  STREAMING_PROTOCOL_RTSP_MJPEG = 2; // RTSP streaming protocol using MJPEG codec. No recording when activated.
 }
 
 // Camera parameters.
 message CameraParameters {
+  reserved 19;
   int32 h264_bitrate = 1; // Bitrate of the h264 stream (bit/sec).
   int32 mjpg_bitrate = 2; // Bitrate of the MJPG stream used for still pictures (bit/sec).
 
@@ -839,6 +840,10 @@ message CameraParameters {
   int32 sharpness = 16; // Sharpness (-20..20), -20 as default. Only available on Ultra.
   int32 backlight_compensation = 17; // Backlight compensation (-150..150), 10 as default. Only available on Ultra.
   int32 denoise = 18; // Noise reduction (-20..20), -20 as default. Only available on Ultra.
+  bool ehdr_enabled = 21; // Enable eHDR mode. Default true. Only available on Ultra.
+  int32 ehdr_exposure_min_number = 22; // Minimum number of eHDR frames. (1..4), default 1. Only available on Ultra.
+  // Maximum number of eHDR frames. (1..4), default 2. Only on Ultra. Setting larger than 2 can reduce the framerate.
+  int32 ehdr_exposure_max_number = 23;
 
   Resolution resolution = 6; // Stream, recording and image resolution (deprecated).
   Resolution stream_resolution = 10; // Stream resolution.
@@ -846,7 +851,6 @@ message CameraParameters {
   StreamingProtocol streaming_protocol = 20; // Streaming protocol.
   Framerate framerate = 7; // Stream and recording framerate.
   Camera camera = 8; // Which camera the parameters belong to.
-  bool fixed_framerate = 19; // Prioritize fixed frame rate over quality on Ultra.
 }
 
 // Available temperature units.