diff --git a/.vscode/launch.json b/.vscode/launch.json
index db975903dc2..b7a3e1428fb 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -50,7 +50,8 @@
         "ACCOUNTS_URL": "http://localhost:3000",
         // "SERVER_PROVIDER":"uweb"
         "SERVER_PROVIDER":"ws",
-        "MODEL_VERSION": ""
+        "MODEL_VERSION": "",
+        "ELASTIC_INDEX_NAME": "local_storage_index"
         
         // "RETRANSLATE_URL": "http://127.0.0.1:4500",
         //"RETRANSLATE_URL": "https://208.167.249.201",
diff --git a/server-plugins/activity-resources/src/references.ts b/server-plugins/activity-resources/src/references.ts
index 5d03b7c0183..de6e5308935 100644
--- a/server-plugins/activity-resources/src/references.ts
+++ b/server-plugins/activity-resources/src/references.ts
@@ -101,13 +101,11 @@ export async function getPersonNotificationTxes (
   }
 
   const res: Tx[] = []
-  const collaboratorsTx = await getCollaboratorsTxes(reference, control, receiver)
+  const doc = (await control.findAll(reference.srcDocClass, { _id: reference.srcDocId }))[0]
 
-  if (collaboratorsTx !== undefined) {
-    res.push(collaboratorsTx)
-  }
+  const collaboratorsTx = await getCollaboratorsTxes(reference, control, receiver, doc)
 
-  const doc = (await control.findAll(reference.srcDocClass, { _id: reference.srcDocId }))[0]
+  res.push(...collaboratorsTx)
 
   if (doc === undefined) {
     return res
@@ -157,16 +155,27 @@ async function isSpaceAvailable (user: PersonAccount, spaceId: Ref<Space>, contr
 async function getCollaboratorsTxes (
   reference: Data<ActivityReference>,
   control: TriggerControl,
-  receiver: Account
-): Promise<TxMixin<Doc, Doc> | undefined> {
+  receiver: Account,
+  object?: Doc
+): Promise<TxMixin<Doc, Doc>[]> {
   const { hierarchy } = control
+  const res: TxMixin<Doc, Doc>[] = []
+
+  if (object !== undefined) {
+    // Add user to collaborators of object where user is mentioned
+    const objectTx = getPushCollaboratorTx(control, receiver._id, object)
+
+    if (objectTx !== undefined) {
+      res.push(objectTx)
+    }
+  }
 
   if (reference.attachedDocClass === undefined || reference.attachedDocId === undefined) {
-    return undefined
+    return res
   }
 
   if (!hierarchy.isDerived(reference.attachedDocClass, activity.class.ActivityMessage)) {
-    return undefined
+    return res
   }
 
   const message = (
@@ -180,10 +189,17 @@ async function getCollaboratorsTxes (
   )[0]
 
   if (message === undefined) {
-    return undefined
+    return res
   }
 
-  return getPushCollaboratorTx(control, receiver._id, message)
+  // Add user to collaborators of message where user is mentioned
+  const messageTx = getPushCollaboratorTx(control, receiver._id, message)
+
+  if (messageTx !== undefined) {
+    res.push(messageTx)
+  }
+
+  return res
 }
 
 async function isReferenceAlreadyNotified (
diff --git a/server-plugins/chunter-resources/src/index.ts b/server-plugins/chunter-resources/src/index.ts
index ad2b6fbeac0..3f9eed56742 100644
--- a/server-plugins/chunter-resources/src/index.ts
+++ b/server-plugins/chunter-resources/src/index.ts
@@ -36,11 +36,12 @@ import core, {
   TxCollectionCUD,
   TxCreateDoc,
   TxCUD,
+  TxMixin,
   TxProcessor,
   TxRemoveDoc,
   TxUpdateDoc
 } from '@hcengineering/core'
-import notification, { NotificationContent } from '@hcengineering/notification'
+import notification, { Collaborators, NotificationContent } from '@hcengineering/notification'
 import { getMetadata, IntlString } from '@hcengineering/platform'
 import serverCore, { TriggerControl } from '@hcengineering/server-core'
 import {
@@ -197,16 +198,24 @@ async function OnChatMessageCreated (tx: TxCUD<Doc>, control: TriggerControl): P
   }
 
   if (isChannel && !(targetDoc as Channel).members.includes(chatMessage.modifiedBy)) {
-    res.push(
-      control.txFactory.createTxUpdateDoc(targetDoc._class, targetDoc.space, targetDoc._id, {
-        $push: { members: chatMessage.modifiedBy }
-      })
-    )
+    res.push(...joinChannel(control, targetDoc as Channel, chatMessage.modifiedBy))
   }
 
   return res
 }
 
+function joinChannel (control: TriggerControl, channel: Channel, user: Ref<Account>): Tx[] {
+  if (channel.members.includes(user)) {
+    return []
+  }
+
+  return [
+    control.txFactory.createTxUpdateDoc(channel._class, channel.space, channel._id, {
+      $push: { members: user }
+    })
+  ]
+}
+
 async function OnThreadMessageDeleted (tx: Tx, control: TriggerControl): Promise<Tx[]> {
   const hierarchy = control.hierarchy
   const removeTx = TxProcessor.extractTx(tx) as TxRemoveDoc<ThreadMessage>
@@ -252,7 +261,8 @@ export async function ChunterTrigger (tx: Tx, control: TriggerControl): Promise<
   const res = await Promise.all([
     OnThreadMessageCreated(tx, control),
     OnThreadMessageDeleted(tx, control),
-    OnChatMessageCreated(tx as TxCUD<Doc>, control)
+    OnChatMessageCreated(tx as TxCUD<Doc>, control),
+    OnCollaboratorsChanged(tx as TxMixin<Doc, Collaborators>, control)
   ])
   return res.flat()
 }
@@ -462,6 +472,26 @@ async function OnChannelMembersChanged (tx: TxUpdateDoc<Channel>, control: Trigg
   return res
 }
 
+async function OnCollaboratorsChanged (tx: TxMixin<Doc, Collaborators>, control: TriggerControl): Promise<Tx[]> {
+  if (tx._class !== core.class.TxMixin || tx.mixin !== notification.mixin.Collaborators) return []
+
+  if (!control.hierarchy.isDerived(tx.objectClass, chunter.class.Channel)) return []
+
+  const doc = (await control.findAll(tx.objectClass, { _id: tx.objectId }))[0] as Channel | undefined
+
+  if (doc === undefined) return []
+  if (doc.private) return []
+
+  const added = combineAttributes([tx.attributes], 'collaborators', '$push', '$each')
+  const res: Tx[] = []
+
+  for (const addedMember of added) {
+    res.push(...joinChannel(control, doc, addedMember))
+  }
+
+  return res
+}
+
 // eslint-disable-next-line @typescript-eslint/explicit-function-return-type
 export default async () => ({
   trigger: {