diff --git a/services/identity/src/database.rs b/services/identity/src/database.rs
--- a/services/identity/src/database.rs
+++ b/services/identity/src/database.rs
@@ -55,7 +55,7 @@
 pub use grpc_clients::identity::DeviceType;
 
 mod device_list;
-pub use device_list::{DeviceListRow, DeviceRow};
+pub use device_list::{DeviceListRow, DeviceListUpdate, DeviceRow};
 
 use self::device_list::PreKey;
 
diff --git a/services/identity/src/database/device_list.rs b/services/identity/src/database/device_list.rs
--- a/services/identity/src/database/device_list.rs
+++ b/services/identity/src/database/device_list.rs
@@ -66,6 +66,13 @@
   pub pre_key_signature: String,
 }
 
+/// A struct representing device list update request
+/// payload; issued by the primary device
+#[derive(serde::Deserialize)]
+pub struct DeviceListUpdate {
+  devices: Vec<String>,
+}
+
 impl DeviceRow {
   pub fn from_device_key_upload(
     user_id: impl Into<String>,
diff --git a/services/identity/src/grpc_services/authenticated.rs b/services/identity/src/grpc_services/authenticated.rs
--- a/services/identity/src/grpc_services/authenticated.rs
+++ b/services/identity/src/grpc_services/authenticated.rs
@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
 use crate::config::CONFIG;
-use crate::database::DeviceListRow;
+use crate::database::{DeviceListRow, DeviceListUpdate};
 use crate::ddb_utils::Identifier;
 use crate::{
   client_service::{
@@ -26,6 +26,7 @@
   InboundKeyInfo, InboundKeysForUserRequest, InboundKeysForUserResponse,
   KeyserverKeysResponse, OutboundKeyInfo, OutboundKeysForUserRequest,
   OutboundKeysForUserResponse, RefreshUserPrekeysRequest,
+  UpdateDeviceListRequest, UpdateDeviceListResponse,
   UpdateUserPasswordFinishRequest, UpdateUserPasswordStartRequest,
   UpdateUserPasswordStartResponse, UploadOneTimeKeysRequest,
 };
@@ -412,6 +413,13 @@
       device_list_updates: stringified_updates,
     }))
   }
+
+  async fn update_device_list_for_user(
+    &self,
+    _request: tonic::Request<UpdateDeviceListRequest>,
+  ) -> Result<Response<UpdateDeviceListResponse>, tonic::Status> {
+    Err(tonic::Status::unimplemented("not implemented"))
+  }
 }
 
 // raw device list that can be serialized to JSON (and then signed in the future)
@@ -451,6 +459,31 @@
   }
 }
 
+impl TryFrom<UpdateDeviceListRequest> for DeviceListUpdate {
+  type Error = tonic::Status;
+  fn try_from(request: UpdateDeviceListRequest) -> Result<Self, Self::Error> {
+    serde_json::from_str(&request.new_device_list).map_err(|err| {
+      error!("Failed to deserialize device list update: {}", err);
+      tonic::Status::failed_precondition("unexpected error")
+    })
+  }
+}
+
+impl TryFrom<SignedDeviceList> for UpdateDeviceListResponse {
+  type Error = tonic::Status;
+  fn try_from(signed_list: SignedDeviceList) -> Result<Self, Self::Error> {
+    let stringified_response_payload = serde_json::to_string(&signed_list)
+      .map_err(|err| {
+        error!("Failed to serialize device list response: {}", err);
+        tonic::Status::failed_precondition("unexpected error")
+      })?;
+    let response = UpdateDeviceListResponse {
+      signed_device_list: stringified_response_payload,
+    };
+    Ok(response)
+  }
+}
+
 #[cfg(test)]
 mod tests {
   use super::*;
diff --git a/shared/protos/identity_auth.proto b/shared/protos/identity_auth.proto
--- a/shared/protos/identity_auth.proto
+++ b/shared/protos/identity_auth.proto
@@ -57,6 +57,9 @@
   // Returns device list history
   rpc GetDeviceListForUser(GetDeviceListRequest) returns
     (GetDeviceListResponse) {}
+
+  rpc UpdateDeviceListForUser(UpdateDeviceListRequest) returns
+    (UpdateDeviceListResponse) {}
 }
 
 // Helper types
@@ -197,3 +200,24 @@
   // }
   repeated string device_list_updates = 1;
 }
+
+// UpdateDeviceListForUser
+
+message UpdateDeviceListRequest {
+  // A stringified JSON object of the following format:
+  // {
+  //   "devices": [<device_id: string>, ...]
+  // }
+  string new_device_list = 1;
+}
+
+message UpdateDeviceListResponse {
+  // A stringified JSON object of the following format:
+  // {
+  //   "rawDeviceList": JSON.stringify({
+  //     "devices": [<device_id: string>, ...]
+  //     "timestamp": <UTC timestamp in milliseconds: int>,
+  //   })
+  // }
+  string signed_device_list = 1;
+}