diff --git a/lib/actions/activity-actions.js b/lib/actions/activity-actions.js
--- a/lib/actions/activity-actions.js
+++ b/lib/actions/activity-actions.js
@@ -1,6 +1,5 @@
 // @flow
 
-import invariant from 'invariant';
 import * as React from 'react';
 
 import {
@@ -9,20 +8,15 @@
 } from '../keyserver-conn/keyserver-call-utils.js';
 import { useKeyserverCall } from '../keyserver-conn/keyserver-call.js';
 import type { CallKeyserverEndpoint } from '../keyserver-conn/keyserver-conn-types.js';
-import {
-  type OutboundDMOperationSpecification,
-  dmOperationSpecificationTypes,
-} from '../shared/dm-ops/dm-op-types.js';
 import { useProcessAndSendDMOperation } from '../shared/dm-ops/process-dm-ops.js';
+import { threadSpecs } from '../shared/threads/thread-specs.js';
 import type {
   ActivityUpdate,
   ActivityUpdateSuccessPayload,
   SetThreadUnreadStatusPayload,
   SetThreadUnreadStatusRequest,
 } from '../types/activity-types.js';
-import type { DMChangeThreadReadStatusOperation } from '../types/dm-ops.js';
 import type { ThreadInfo } from '../types/minimally-encoded-thread-permissions-types';
-import { threadTypeIsThick } from '../types/thread-types-enum.js';
 import { useSelector } from '../utils/redux-utils.js';
 
 export type UpdateActivityInput = {
@@ -124,36 +118,14 @@
   const keyserverCall = useKeyserverCall(setThreadUnreadStatus);
 
   return React.useCallback(
-    async (input: UseSetThreadUnreadStatusInput) => {
-      if (!threadTypeIsThick(input.threadInfo.type)) {
-        const { threadInfo, ...rest } = input;
-        return await keyserverCall({ ...rest });
-      }
-
-      invariant(viewerID, 'viewerID must be set');
-      const { threadInfo } = input;
-      const op: DMChangeThreadReadStatusOperation = {
-        type: 'change_thread_read_status',
-        time: Date.now(),
-        threadID: threadInfo.id,
-        creatorID: viewerID,
-        unread: !threadInfo.currentUser.unread,
-      };
-
-      const opSpecification: OutboundDMOperationSpecification = {
-        type: dmOperationSpecificationTypes.OUTBOUND,
-        op,
-        recipients: {
-          type: 'self_devices',
+    async (input: UseSetThreadUnreadStatusInput) =>
+      threadSpecs[input.threadInfo.type].protocol.setThreadUnreadStatus(
+        { input, viewerID },
+        {
+          processAndSendDMOperation,
+          keyserverSetThreadUnreadStatus: keyserverCall,
         },
-      };
-
-      await processAndSendDMOperation(opSpecification);
-      return {
-        resetToUnread: false,
-        threadID: threadInfo.id,
-      };
-    },
+      ),
 
     [keyserverCall, viewerID, processAndSendDMOperation],
   );
diff --git a/lib/shared/threads/protocols/dm-thread-protocol.js b/lib/shared/threads/protocols/dm-thread-protocol.js
--- a/lib/shared/threads/protocols/dm-thread-protocol.js
+++ b/lib/shared/threads/protocols/dm-thread-protocol.js
@@ -5,6 +5,7 @@
 
 import type { TunnelbrokerSocketState } from '../../../tunnelbroker/tunnelbroker-context.js';
 import type {
+  DMChangeThreadReadStatusOperation,
   DMChangeThreadSettingsOperation,
   DMCreateEntryOperation,
   DMDeleteEntryOperation,
@@ -36,6 +37,8 @@
   DeleteEntryUtils,
   ProtocolEditEntryInput,
   EditEntryUtils,
+  ProtocolSetThreadUnreadStatusInput,
+  SetThreadUnreadStatusUtils,
 } from '../thread-spec.js';
 
 const dmThreadProtocol: ThreadProtocol = Object.freeze({
@@ -393,6 +396,39 @@
       },
     };
   },
+
+  setThreadUnreadStatus: async (
+    input: ProtocolSetThreadUnreadStatusInput,
+    utils: SetThreadUnreadStatusUtils,
+  ) => {
+    const {
+      viewerID,
+      input: { threadInfo },
+    } = input;
+
+    invariant(viewerID, 'viewerID must be set');
+    const op: DMChangeThreadReadStatusOperation = {
+      type: 'change_thread_read_status',
+      time: Date.now(),
+      threadID: threadInfo.id,
+      creatorID: viewerID,
+      unread: !threadInfo.currentUser.unread,
+    };
+
+    const opSpecification: OutboundDMOperationSpecification = {
+      type: dmOperationSpecificationTypes.OUTBOUND,
+      op,
+      recipients: {
+        type: 'self_devices',
+      },
+    };
+
+    await utils.processAndSendDMOperation(opSpecification);
+    return {
+      resetToUnread: false,
+      threadID: threadInfo.id,
+    };
+  },
 });
 
 export { dmThreadProtocol };
diff --git a/lib/shared/threads/protocols/keyserver-thread-protocol.js b/lib/shared/threads/protocols/keyserver-thread-protocol.js
--- a/lib/shared/threads/protocols/keyserver-thread-protocol.js
+++ b/lib/shared/threads/protocols/keyserver-thread-protocol.js
@@ -47,6 +47,8 @@
   DeleteEntryUtils,
   ProtocolEditEntryInput,
   EditEntryUtils,
+  ProtocolSetThreadUnreadStatusInput,
+  SetThreadUnreadStatusUtils,
 } from '../thread-spec.js';
 
 const keyserverThreadProtocol: ThreadProtocol = Object.freeze({
@@ -200,6 +202,16 @@
     protocolInput: ProtocolEditEntryInput,
     utils: EditEntryUtils,
   ) => utils.keyserverEditEntry(protocolInput.input.saveEntryInfo),
+
+  setThreadUnreadStatus: (
+    input: ProtocolSetThreadUnreadStatusInput,
+    utils: SetThreadUnreadStatusUtils,
+  ) => {
+    const {
+      input: { threadInfo, ...rest },
+    } = input;
+    return utils.keyserverSetThreadUnreadStatus(rest);
+  },
 });
 
 function mediaIDIsKeyserverID(mediaID: string): boolean {
diff --git a/lib/shared/threads/thread-spec.js b/lib/shared/threads/thread-spec.js
--- a/lib/shared/threads/thread-spec.js
+++ b/lib/shared/threads/thread-spec.js
@@ -1,5 +1,6 @@
 // @flow
 
+import type { UseSetThreadUnreadStatusInput } from '../../actions/activity-actions.js';
 import type {
   UseCreateEntryInput,
   UseDeleteEntryInput,
@@ -15,6 +16,10 @@
 import { type MediaMetadataReassignmentAction } from '../../actions/upload-actions.js';
 import type { ProcessOutboundP2PMessagesResult } from '../../tunnelbroker/peer-to-peer-context.js';
 import type { TunnelbrokerSocketState } from '../../tunnelbroker/tunnelbroker-context.js';
+import type {
+  SetThreadUnreadStatusPayload,
+  SetThreadUnreadStatusRequest,
+} from '../../types/activity-types.js';
 import type {
   CreateEntryInfo,
   CreateEntryPayload,
@@ -132,6 +137,15 @@
   +keyserverEditEntry: SaveEntryInfo => Promise<SaveEntryResult>,
 };
 
+export type ProtocolSetThreadUnreadStatusInput = {
+  +input: UseSetThreadUnreadStatusInput,
+  +viewerID: ?string,
+};
+export type SetThreadUnreadStatusUtils = {
+  +processAndSendDMOperation: OutboundDMOperationSpecification => Promise<void>,
+  +keyserverSetThreadUnreadStatus: SetThreadUnreadStatusRequest => Promise<SetThreadUnreadStatusPayload>,
+};
+
 export type ThreadProtocol = {
   +sendTextMessage: (
     message: ProtocolSendTextMessageInput,
@@ -166,6 +180,10 @@
     input: ProtocolEditEntryInput,
     utils: EditEntryUtils,
   ) => Promise<SaveEntryResult>,
+  +setThreadUnreadStatus: (
+    input: ProtocolSetThreadUnreadStatusInput,
+    utils: SetThreadUnreadStatusUtils,
+  ) => Promise<SetThreadUnreadStatusPayload>,
 };
 
 export type ThreadSpec = {