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
@@ -239,6 +239,8 @@
       newMessageInfos: [],
     }: ChangeThreadSettingsPayload);
   },
+
+  supportsCalendarHistory: false,
 });
 
 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
@@ -171,6 +171,8 @@
     const { thick, threadInfo, ...rest } = protocolInput.input;
     return await utils.keyserverChangeThreadSettings({ ...rest });
   },
+
+  supportsCalendarHistory: true,
 });
 
 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
@@ -105,6 +105,7 @@
     input: ProtocolChangeThreadSettingsInput,
     utils: ChangeThreadSettingsUtils,
   ) => Promise<ChangeThreadSettingsPayload>,
+  +supportsCalendarHistory: boolean,
 };
 
 export type ThreadSpec = {
diff --git a/web/calendar/entry.react.js b/web/calendar/entry.react.js
--- a/web/calendar/entry.react.js
+++ b/web/calendar/entry.react.js
@@ -26,6 +26,7 @@
 import { colorIsDark } from 'lib/shared/color-utils.js';
 import { entryKey } from 'lib/shared/entry-utils.js';
 import { useThreadHasPermission } from 'lib/shared/thread-utils.js';
+import { threadSpecs } from 'lib/shared/threads/thread-specs.js';
 import { useTunnelbroker } from 'lib/tunnelbroker/tunnelbroker-context.js';
 import {
   type EntryInfo,
@@ -175,7 +176,7 @@
       let historyButton = null;
       if (
         this.props.entryInfo.id &&
-        !threadTypeIsThick(this.props.threadInfo.type)
+        threadSpecs[this.props.threadInfo.type].protocol.supportsCalendarHistory
       ) {
         historyButton = (
           <a href="#" onClick={this.onHistory}>