diff --git a/README.md b/README.md
index b1dc56c..74301b2 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,20 @@ Use the command below:
 protoc --doc_out=./doc --doc_opt=markdown,docs.md fishjam/**/*.proto
 ```
 
+## Lint and formatting
+
+The files can be formatted using `buf`. 
+Check out [installation page](https://buf.build/docs/installation/) for `buf`.
+
+```
+buf format -w
+```
+
+and linted
+```
+buf lint
+```
+
 ## Copyright and License
 
 Copyright 2023, [Software Mansion](https://swmansion.com/?utm_source=git&utm_medium=readme&utm_campaign=fishjam-protos)
diff --git a/fishjam/media_events/peer/peer.proto b/fishjam/media_events/peer/peer.proto
index 7a8f0d1..93c5085 100644
--- a/fishjam/media_events/peer/peer.proto
+++ b/fishjam/media_events/peer/peer.proto
@@ -6,6 +6,13 @@ import "fishjam/media_events/shared.proto";
 
 // Defines any type of message sent from Peer to Membrane RTC Engine
 message MediaEvent {
+  // SCHEMAS
+
+  message VariantBitrate {
+    media_events.Variant variant = 1;
+    int32 bitrate = 2;
+  }
+
   // MEDIA EVENTS
 
   // Sent when a peer wants to join WebRTC Endpoint.
@@ -36,14 +43,26 @@ message MediaEvent {
   message SdpOffer {
     string sdp_offer = 1;
     map<string, string> track_id_to_metadata_json = 2;
-    map<string, TrackBitrate> track_id_to_bitrates = 3;
+    map<string, TrackBitrates> track_id_to_bitrates = 3;
     map<string, string> mid_to_track_id = 4;
   }
 
   // Sent when Peer wants to update its track's bitrate
-  message TrackBitrate {
+  message TrackBitrates {
     string track_id = 1;
-    int32 bitrate = 2;
+    repeated VariantBitrate variant_bitrates = 2;
+  }
+
+  // Sent when client disables one of the track variants
+  message DisableTrackVariant {
+    string track_id = 1;
+    media_events.Variant variant = 2;
+  }
+
+  // Sent when client enables one of the track variants
+  message EnableTrackVariant {
+    string track_id = 1;
+    media_events.Variant variant = 2;
   }
 
   oneof content {
@@ -54,6 +73,8 @@ message MediaEvent {
     RenegotiateTracks renegotiate_tracks = 5;
     media_events.Candidate candidate = 6;
     SdpOffer sdp_offer = 7;
-    TrackBitrate track_bitrate = 8;
+    TrackBitrates track_bitrates = 8;
+    EnableTrackVariant enable_track_variant = 9;
+    DisableTrackVariant disable_track_variant = 10;
   }
 }
diff --git a/fishjam/media_events/server/server.proto b/fishjam/media_events/server/server.proto
index a06e590..9deee49 100644
--- a/fishjam/media_events/server/server.proto
+++ b/fishjam/media_events/server/server.proto
@@ -7,11 +7,21 @@ import "fishjam/media_events/shared.proto";
 // Defines any type of message sent from Membrane RTC Engine to Peer
 message MediaEvent {
   // SCHEMAS
+  message Track {
+    message SimulcastConfig {
+      bool enabled = 1;
+      repeated media_events.Variant enabled_variants = 2;
+      repeated media_events.Variant disabled_variants = 3;
+    }
+
+    string metadata_json = 1;
+    SimulcastConfig simulcast_config = 2;
+  }
 
   message Endpoint {
     string endpoint_type = 2;
     string metadata_json = 3;
-    map<string, string> track_id_to_metadata_json = 4;
+    map<string, Track> track_id_to_track = 4;
   }
 
   message IceServer {
@@ -38,7 +48,7 @@ message MediaEvent {
   //  Sent to informs that one of the peers has added one or more tracks.
   message TracksAdded {
     string endpoint_id = 1;
-    map<string, string> track_id_to_metadata_json = 2;
+    map<string, Track> track_id_to_track = 2;
   }
 
   //  Sent to informs that one of the peers has removed one or more tracks.
@@ -56,7 +66,7 @@ message MediaEvent {
   // Sent to the peer after connecting to the WebRTC Endpoint.
   message Connected {
     string endpoint_id = 1;
-    map<string, Endpoint> endpoints_id_to_endpoint = 2;
+    map<string, Endpoint> endpoint_id_to_endpoint = 2;
     repeated IceServer ice_servers = 3;
   }
 
@@ -100,6 +110,27 @@ message MediaEvent {
     Status status = 2;
   }
 
+  // Informs that track's variant has been changed
+  message TrackVariantSwitched {
+    string endpoint_id = 1;
+    string track_id = 2;
+    media_events.Variant variant = 3;
+  }
+
+  // Sent when track's variant has been disabled
+  message TrackVariantDisabled {
+    string endpoint_id = 1;
+    string track_id = 2;
+    media_events.Variant variant = 3;
+  }
+
+  // Sent when track's variant has been enabled
+  message TrackVariantEnabled {
+    string endpoint_id = 1;
+    string track_id = 2;
+    media_events.Variant variant = 3;
+  }
+
   oneof content {
     EndpointUpdated endpoint_updated = 1;
     TrackUpdated track_updated = 2;
@@ -113,5 +144,8 @@ message MediaEvent {
     media_events.Candidate candidate = 10;
     SdpAnswer sdp_answer = 11;
     VadNotification vad_notification = 12;
+    TrackVariantSwitched track_variant_switched = 13;
+    TrackVariantDisabled track_variant_disabled = 14;
+    TrackVariantEnabled track_variant_enabled = 15;
   }
 }
diff --git a/fishjam/media_events/shared.proto b/fishjam/media_events/shared.proto
index a56f12a..4b2ad4c 100644
--- a/fishjam/media_events/shared.proto
+++ b/fishjam/media_events/shared.proto
@@ -9,3 +9,10 @@ message Candidate {
   string sdp_mid = 3;
   string username_fragment = 4;
 }
+
+enum Variant {
+  VARIANT_UNSPECIFIED = 0;
+  VARIANT_LOW = 1;
+  VARIANT_MEDIUM = 2;
+  VARIANT_HIGH = 3;
+}
diff --git a/fishjam_protos/lib/fishjam/media_events/peer/peer.pb.ex b/fishjam_protos/lib/fishjam/media_events/peer/peer.pb.ex
index 2c5328c..11e4b43 100644
--- a/fishjam_protos/lib/fishjam/media_events/peer/peer.pb.ex
+++ b/fishjam_protos/lib/fishjam/media_events/peer/peer.pb.ex
@@ -1,3 +1,12 @@
+defmodule Fishjam.MediaEvents.Peer.MediaEvent.VariantBitrate do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :variant, 1, type: Fishjam.MediaEvents.Variant, enum: true
+  field :bitrate, 2, type: :int32
+end
+
 defmodule Fishjam.MediaEvents.Peer.MediaEvent.Connect do
   @moduledoc false
 
@@ -50,7 +59,7 @@ defmodule Fishjam.MediaEvents.Peer.MediaEvent.SdpOffer.TrackIdToBitratesEntry do
   use Protobuf, map: true, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
 
   field :key, 1, type: :string
-  field :value, 2, type: Fishjam.MediaEvents.Peer.MediaEvent.TrackBitrate
+  field :value, 2, type: Fishjam.MediaEvents.Peer.MediaEvent.TrackBitrates
 end
 
 defmodule Fishjam.MediaEvents.Peer.MediaEvent.SdpOffer.MidToTrackIdEntry do
@@ -88,13 +97,35 @@ defmodule Fishjam.MediaEvents.Peer.MediaEvent.SdpOffer do
     map: true
 end
 
-defmodule Fishjam.MediaEvents.Peer.MediaEvent.TrackBitrate do
+defmodule Fishjam.MediaEvents.Peer.MediaEvent.TrackBitrates do
   @moduledoc false
 
   use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
 
   field :track_id, 1, type: :string, json_name: "trackId"
-  field :bitrate, 2, type: :int32
+
+  field :variant_bitrates, 2,
+    repeated: true,
+    type: Fishjam.MediaEvents.Peer.MediaEvent.VariantBitrate,
+    json_name: "variantBitrates"
+end
+
+defmodule Fishjam.MediaEvents.Peer.MediaEvent.DisableTrackVariant do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :track_id, 1, type: :string, json_name: "trackId"
+  field :variant, 2, type: Fishjam.MediaEvents.Variant, enum: true
+end
+
+defmodule Fishjam.MediaEvents.Peer.MediaEvent.EnableTrackVariant do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :track_id, 1, type: :string, json_name: "trackId"
+  field :variant, 2, type: Fishjam.MediaEvents.Variant, enum: true
 end
 
 defmodule Fishjam.MediaEvents.Peer.MediaEvent do
@@ -129,8 +160,18 @@ defmodule Fishjam.MediaEvents.Peer.MediaEvent do
     json_name: "sdpOffer",
     oneof: 0
 
-  field :track_bitrate, 8,
-    type: Fishjam.MediaEvents.Peer.MediaEvent.TrackBitrate,
-    json_name: "trackBitrate",
+  field :track_bitrates, 8,
+    type: Fishjam.MediaEvents.Peer.MediaEvent.TrackBitrates,
+    json_name: "trackBitrates",
+    oneof: 0
+
+  field :enable_track_variant, 9,
+    type: Fishjam.MediaEvents.Peer.MediaEvent.EnableTrackVariant,
+    json_name: "enableTrackVariant",
+    oneof: 0
+
+  field :disable_track_variant, 10,
+    type: Fishjam.MediaEvents.Peer.MediaEvent.DisableTrackVariant,
+    json_name: "disableTrackVariant",
     oneof: 0
 end
diff --git a/fishjam_protos/lib/fishjam/media_events/server/server.pb.ex b/fishjam_protos/lib/fishjam/media_events/server/server.pb.ex
index 09ab256..d12d4b0 100644
--- a/fishjam_protos/lib/fishjam/media_events/server/server.pb.ex
+++ b/fishjam_protos/lib/fishjam/media_events/server/server.pb.ex
@@ -8,13 +8,45 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.VadNotification.Status do
   field :STATUS_SPEECH, 2
 end
 
-defmodule Fishjam.MediaEvents.Server.MediaEvent.Endpoint.TrackIdToMetadataJsonEntry do
+defmodule Fishjam.MediaEvents.Server.MediaEvent.Track.SimulcastConfig do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :enabled, 1, type: :bool
+
+  field :enabled_variants, 2,
+    repeated: true,
+    type: Fishjam.MediaEvents.Variant,
+    json_name: "enabledVariants",
+    enum: true
+
+  field :disabled_variants, 3,
+    repeated: true,
+    type: Fishjam.MediaEvents.Variant,
+    json_name: "disabledVariants",
+    enum: true
+end
+
+defmodule Fishjam.MediaEvents.Server.MediaEvent.Track do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :metadata_json, 1, type: :string, json_name: "metadataJson"
+
+  field :simulcast_config, 2,
+    type: Fishjam.MediaEvents.Server.MediaEvent.Track.SimulcastConfig,
+    json_name: "simulcastConfig"
+end
+
+defmodule Fishjam.MediaEvents.Server.MediaEvent.Endpoint.TrackIdToTrackEntry do
   @moduledoc false
 
   use Protobuf, map: true, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
 
   field :key, 1, type: :string
-  field :value, 2, type: :string
+  field :value, 2, type: Fishjam.MediaEvents.Server.MediaEvent.Track
 end
 
 defmodule Fishjam.MediaEvents.Server.MediaEvent.Endpoint do
@@ -25,10 +57,10 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.Endpoint do
   field :endpoint_type, 2, type: :string, json_name: "endpointType"
   field :metadata_json, 3, type: :string, json_name: "metadataJson"
 
-  field :track_id_to_metadata_json, 4,
+  field :track_id_to_track, 4,
     repeated: true,
-    type: Fishjam.MediaEvents.Server.MediaEvent.Endpoint.TrackIdToMetadataJsonEntry,
-    json_name: "trackIdToMetadataJson",
+    type: Fishjam.MediaEvents.Server.MediaEvent.Endpoint.TrackIdToTrackEntry,
+    json_name: "trackIdToTrack",
     map: true
 end
 
@@ -61,13 +93,13 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.TrackUpdated do
   field :metadata_json, 3, type: :string, json_name: "metadataJson"
 end
 
-defmodule Fishjam.MediaEvents.Server.MediaEvent.TracksAdded.TrackIdToMetadataJsonEntry do
+defmodule Fishjam.MediaEvents.Server.MediaEvent.TracksAdded.TrackIdToTrackEntry do
   @moduledoc false
 
   use Protobuf, map: true, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
 
   field :key, 1, type: :string
-  field :value, 2, type: :string
+  field :value, 2, type: Fishjam.MediaEvents.Server.MediaEvent.Track
 end
 
 defmodule Fishjam.MediaEvents.Server.MediaEvent.TracksAdded do
@@ -77,10 +109,10 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.TracksAdded do
 
   field :endpoint_id, 1, type: :string, json_name: "endpointId"
 
-  field :track_id_to_metadata_json, 2,
+  field :track_id_to_track, 2,
     repeated: true,
-    type: Fishjam.MediaEvents.Server.MediaEvent.TracksAdded.TrackIdToMetadataJsonEntry,
-    json_name: "trackIdToMetadataJson",
+    type: Fishjam.MediaEvents.Server.MediaEvent.TracksAdded.TrackIdToTrackEntry,
+    json_name: "trackIdToTrack",
     map: true
 end
 
@@ -102,7 +134,7 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.EndpointAdded do
   field :metadata_json, 2, type: :string, json_name: "metadataJson"
 end
 
-defmodule Fishjam.MediaEvents.Server.MediaEvent.Connected.EndpointsIdToEndpointEntry do
+defmodule Fishjam.MediaEvents.Server.MediaEvent.Connected.EndpointIdToEndpointEntry do
   @moduledoc false
 
   use Protobuf, map: true, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
@@ -118,10 +150,10 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.Connected do
 
   field :endpoint_id, 1, type: :string, json_name: "endpointId"
 
-  field :endpoints_id_to_endpoint, 2,
+  field :endpoint_id_to_endpoint, 2,
     repeated: true,
-    type: Fishjam.MediaEvents.Server.MediaEvent.Connected.EndpointsIdToEndpointEntry,
-    json_name: "endpointsIdToEndpoint",
+    type: Fishjam.MediaEvents.Server.MediaEvent.Connected.EndpointIdToEndpointEntry,
+    json_name: "endpointIdToEndpoint",
     map: true
 
   field :ice_servers, 3,
@@ -197,6 +229,36 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent.VadNotification do
   field :status, 2, type: Fishjam.MediaEvents.Server.MediaEvent.VadNotification.Status, enum: true
 end
 
+defmodule Fishjam.MediaEvents.Server.MediaEvent.TrackVariantSwitched do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :endpoint_id, 1, type: :string, json_name: "endpointId"
+  field :track_id, 2, type: :string, json_name: "trackId"
+  field :variant, 3, type: Fishjam.MediaEvents.Variant, enum: true
+end
+
+defmodule Fishjam.MediaEvents.Server.MediaEvent.TrackVariantDisabled do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :endpoint_id, 1, type: :string, json_name: "endpointId"
+  field :track_id, 2, type: :string, json_name: "trackId"
+  field :variant, 3, type: Fishjam.MediaEvents.Variant, enum: true
+end
+
+defmodule Fishjam.MediaEvents.Server.MediaEvent.TrackVariantEnabled do
+  @moduledoc false
+
+  use Protobuf, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :endpoint_id, 1, type: :string, json_name: "endpointId"
+  field :track_id, 2, type: :string, json_name: "trackId"
+  field :variant, 3, type: Fishjam.MediaEvents.Variant, enum: true
+end
+
 defmodule Fishjam.MediaEvents.Server.MediaEvent do
   @moduledoc false
 
@@ -253,4 +315,19 @@ defmodule Fishjam.MediaEvents.Server.MediaEvent do
     type: Fishjam.MediaEvents.Server.MediaEvent.VadNotification,
     json_name: "vadNotification",
     oneof: 0
+
+  field :track_variant_switched, 13,
+    type: Fishjam.MediaEvents.Server.MediaEvent.TrackVariantSwitched,
+    json_name: "trackVariantSwitched",
+    oneof: 0
+
+  field :track_variant_disabled, 14,
+    type: Fishjam.MediaEvents.Server.MediaEvent.TrackVariantDisabled,
+    json_name: "trackVariantDisabled",
+    oneof: 0
+
+  field :track_variant_enabled, 15,
+    type: Fishjam.MediaEvents.Server.MediaEvent.TrackVariantEnabled,
+    json_name: "trackVariantEnabled",
+    oneof: 0
 end
diff --git a/fishjam_protos/lib/fishjam/media_events/shared.pb.ex b/fishjam_protos/lib/fishjam/media_events/shared.pb.ex
index 9323a17..d91ee06 100644
--- a/fishjam_protos/lib/fishjam/media_events/shared.pb.ex
+++ b/fishjam_protos/lib/fishjam/media_events/shared.pb.ex
@@ -1,3 +1,14 @@
+defmodule Fishjam.MediaEvents.Variant do
+  @moduledoc false
+
+  use Protobuf, enum: true, syntax: :proto3, protoc_gen_elixir_version: "0.13.0"
+
+  field :VARIANT_UNSPECIFIED, 0
+  field :VARIANT_LOW, 1
+  field :VARIANT_MEDIUM, 2
+  field :VARIANT_HIGH, 3
+end
+
 defmodule Fishjam.MediaEvents.Candidate do
   @moduledoc false