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
@@ -916,6 +916,8 @@
     threadActivityUpdatedByDMActivityHandler: true,
 
     membershipMessageNotifAction: messageNotifyTypes.SET_UNREAD,
+
+    shouldConvertIDs: false,
   });
 
 function pendingThreadType(numberOfOtherMembers: number) {
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
@@ -674,6 +674,8 @@
     threadActivityUpdatedByDMActivityHandler: false,
 
     membershipMessageNotifAction: messageNotifyTypes.NONE,
+
+    shouldConvertIDs: true,
   });
 
 function pendingThreadType(numberOfOtherMembers: number) {
diff --git a/lib/shared/threads/protocols/thread-protocols.js b/lib/shared/threads/protocols/thread-protocols.js
--- a/lib/shared/threads/protocols/thread-protocols.js
+++ b/lib/shared/threads/protocols/thread-protocols.js
@@ -9,7 +9,10 @@
   keyserverThreadProtocol,
 ];
 
-function getProtocolByThreadID(threadID: string): ?ThreadProtocol<any> {
+function getProtocolByThreadID(threadID?: ?string): ?ThreadProtocol<any> {
+  if (!threadID) {
+    return null;
+  }
   return protocols().find(p => p.threadIDMatchesProtocol(threadID));
 }
 
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
@@ -398,6 +398,7 @@
   // https://linear.app/comm/issue/ENG-10729/consider-merging-activity-handlers
   +threadActivityUpdatedByDMActivityHandler: boolean,
   +membershipMessageNotifAction: MessageNotifyType,
+  +shouldConvertIDs: boolean,
 };
 
 export type ThreadSpec<
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -40,12 +40,7 @@
 import type { UserInfo, UserInfos } from './user-types.js';
 import type { SpecialRole } from '../permissions/special-roles.js';
 import { type ThreadEntity } from '../utils/entity-text.js';
-import {
-  tID,
-  tShape,
-  tUserID,
-  thickIDRegex,
-} from '../utils/validation-utils.js';
+import { tID, tShape, tUserID } from '../utils/validation-utils.js';
 
 export type LegacyMemberInfo = {
   +id: string,
@@ -532,7 +527,3 @@
   +threadInfo: ThreadInfo,
   +pendingPersonalThreadUserInfo?: UserInfo,
 };
-
-export function threadIDIsThick(threadID: string): boolean {
-  return thickIDRegex.test(threadID);
-}
diff --git a/web/redux/initial-state-gate.js b/web/redux/initial-state-gate.js
--- a/web/redux/initial-state-gate.js
+++ b/web/redux/initial-state-gate.js
@@ -11,9 +11,9 @@
 import type { UserStoreOperation } from 'lib/ops/user-store-ops.js';
 import { getMessageSearchStoreOps } from 'lib/reducers/db-ops-reducer.js';
 import { allUpdatesCurrentAsOfSelector } from 'lib/selectors/keyserver-selectors.js';
+import { getProtocolByThreadID } from 'lib/shared/threads/protocols/thread-protocols.js';
 import type { RawThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type { ClientStore } from 'lib/types/store-ops-types.js';
-import { threadIDIsThick } from 'lib/types/thread-types.js';
 import { getConfig } from 'lib/utils/config.js';
 import { convertIDToNewSchema } from 'lib/utils/migration-utils.js';
 import { entries, values } from 'lib/utils/objects.js';
@@ -97,10 +97,11 @@
     void (async () => {
       try {
         let urlInfo = infoFromURL(decodeURI(window.location.href));
-        const isThickThreadOpen =
-          urlInfo.thread && threadIDIsThick(urlInfo.thread);
+        const protocol = getProtocolByThreadID(urlInfo.thread);
+        const isNonConvertibleThreadOpen =
+          urlInfo.thread && protocol && !protocol.shouldConvertIDs;
         // Handle older links
-        if (urlInfo.thread && !isThickThreadOpen) {
+        if (urlInfo.thread && !isNonConvertibleThreadOpen) {
           urlInfo = {
             ...urlInfo,
             thread: convertIDToNewSchema(
@@ -121,7 +122,7 @@
           allUpdatesCurrentAsOf,
         });
 
-        if (isThickThreadOpen) {
+        if (isNonConvertibleThreadOpen) {
           payload.navInfo.activeChatThreadID = urlInfo.thread;
         }