diff --git a/integrations/whatsapp/integration.definition.ts b/integrations/whatsapp/integration.definition.ts
index 7f9cc3d9f6a..3a690a7a4ce 100644
--- a/integrations/whatsapp/integration.definition.ts
+++ b/integrations/whatsapp/integration.definition.ts
@@ -157,7 +157,7 @@ const defaultBotPhoneNumberId = {
 }
 
 export const INTEGRATION_NAME = 'whatsapp'
-export const INTEGRATION_VERSION = '4.15.0'
+export const INTEGRATION_VERSION = '4.16.0'
 export default new IntegrationDefinition({
   name: INTEGRATION_NAME,
   version: INTEGRATION_VERSION,
@@ -358,6 +358,10 @@ export default new IntegrationDefinition({
             title: 'User Phone Number',
             description: 'Phone number of the WhatsApp user having a conversation with the bot.',
           },
+          userId: {
+            title: 'User ID',
+            description: 'WhatsApp stable user ID of the user having a conversation with the bot.',
+          },
         },
       },
     },
@@ -376,6 +380,15 @@ export default new IntegrationDefinition({
         title: 'Phone Number',
         description: 'WhatsApp phone number of the user',
       },
+      username: {
+        title: 'Username',
+        description: 'WhatsApp username of the user (when opted in to username privacy)',
+      },
+      whatsappUserId: {
+        title: 'WhatsApp User ID',
+        description:
+          "WhatsApp's stable user ID (user_id) of the user, present in both opted-in and non-opted-in payloads",
+      },
     },
   },
   actions: {
diff --git a/integrations/whatsapp/src/channels/channel.ts b/integrations/whatsapp/src/channels/channel.ts
index 7df116a36d3..400526a50ee 100644
--- a/integrations/whatsapp/src/channels/channel.ts
+++ b/integrations/whatsapp/src/channels/channel.ts
@@ -267,7 +267,9 @@ async function _send({ client, ctx, conversation, logger, message, ack }: SendMe
 
   const whatsapp = await getAuthenticatedWhatsappClient(client, ctx)
   const botPhoneNumberId = conversation.tags.botPhoneNumberId
-  const userPhoneNumber = conversation.tags.userPhone
+  // For users opted in to username privacy, no phone number is available and the stable
+  // WhatsApp user_id is used as the recipient instead.
+  const recipient = conversation.tags.userPhone ?? conversation.tags.userId
   const messageType = message._type
 
   if (!botPhoneNumberId) {
@@ -277,10 +279,12 @@ async function _send({ client, ctx, conversation, logger, message, ack }: SendMe
     return
   }
 
-  if (!userPhoneNumber) {
+  if (!recipient) {
     logger
       .forBot()
-      .error("Cannot send message to WhatsApp because the user's phone number isn't set in the conversation tags")
+      .error(
+        "Cannot send message to WhatsApp because neither the user's phone number nor user ID is set in the conversation tags"
+      )
     return
   }
 
@@ -290,7 +294,7 @@ async function _send({ client, ctx, conversation, logger, message, ack }: SendMe
         logger.forBot().info(`Retrying to send ${messageType} message to WhatsApp (attempt ${i + 1}/${MAX_ATTEMPT})...`)
       }
 
-      const result = await whatsapp.sendMessage(botPhoneNumberId, userPhoneNumber, message)
+      const result = await whatsapp.sendMessage(botPhoneNumberId, recipient, message)
       const repeat = 'error' in result && THROTTLING_CODES.has(result.error?.code ?? 0)
       return {
         repeat,
diff --git a/integrations/whatsapp/src/misc/types.ts b/integrations/whatsapp/src/misc/types.ts
index c21b1d4d667..093de76f366 100644
--- a/integrations/whatsapp/src/misc/types.ts
+++ b/integrations/whatsapp/src/misc/types.ts
@@ -2,16 +2,19 @@ import { z } from '@botpress/sdk'
 import { qualityScoreSchema } from 'definitions/events'
 
 const WhatsAppContactSchema = z.object({
-  wa_id: z.string(),
+  wa_id: z.string().optional(),
+  user_id: z.string().optional(),
   profile: z
     .object({
       name: z.string().optional(),
+      username: z.string().optional(),
     })
     .optional(),
 })
 
 const WhatsAppBaseMessageSchema = z.object({
-  from: z.string(),
+  from: z.string().optional(),
+  from_user_id: z.string().optional(),
   id: z.string(),
   timestamp: z.string(),
   type: z.string(),
diff --git a/integrations/whatsapp/src/webhook/handlers/messages.ts b/integrations/whatsapp/src/webhook/handlers/messages.ts
index 5a471e53fec..5bb75e7e153 100644
--- a/integrations/whatsapp/src/webhook/handlers/messages.ts
+++ b/integrations/whatsapp/src/webhook/handlers/messages.ts
@@ -43,41 +43,61 @@ export const messagesHandler = async (
   const phoneNumberId = value.metadata.phone_number_id
   await whatsapp.markAsRead(phoneNumberId, message.id)
 
-  const formatPhoneNumberResponse = safeFormatPhoneNumber(message.from)
-  if (formatPhoneNumberResponse.success === false) {
-    const distinctId = formatPhoneNumberResponse.error.id
-    await posthogHelper.sendPosthogEvent(
-      {
-        distinctId: distinctId ?? 'no id',
-        event: 'invalid_phone_number',
-        properties: {
-          from: 'handler',
-          phoneNumber: message.from,
+  const { contacts } = value
+  const contact = contacts?.[0]
+  if (!contact) {
+    logger.forBot().warn('No contacts found, ignoring message')
+    return
+  }
+
+  const waUserId = message.from_user_id ?? contact.user_id
+
+  let userPhone: string | undefined
+  if (message.from) {
+    const formatPhoneNumberResponse = safeFormatPhoneNumber(message.from)
+    if (formatPhoneNumberResponse.success === false) {
+      const distinctId = formatPhoneNumberResponse.error.id
+      await posthogHelper.sendPosthogEvent(
+        {
+          distinctId: distinctId ?? 'no id',
+          event: 'invalid_phone_number',
+          properties: {
+            from: 'handler',
+            phoneNumber: message.from,
+          },
         },
-      },
-      { integrationName: INTEGRATION_NAME, integrationVersion: INTEGRATION_VERSION, key: bp.secrets.POSTHOG_KEY }
-    )
-    const errorMessage = formatPhoneNumberResponse.error.message
-    logger.error(`Failed to parse phone number "${message.from}": ${errorMessage}`)
+        { integrationName: INTEGRATION_NAME, integrationVersion: INTEGRATION_VERSION, key: bp.secrets.POSTHOG_KEY }
+      )
+      const errorMessage = formatPhoneNumberResponse.error.message
+      logger.error(`Failed to parse phone number "${message.from}": ${errorMessage}`)
+    }
+    userPhone = formatPhoneNumberResponse.success ? formatPhoneNumberResponse.phoneNumber : message.from
   }
 
   const { conversation } = await client.getOrCreateConversation({
     channel: 'channel',
     tags: {
-      userPhone: formatPhoneNumberResponse.success ? formatPhoneNumberResponse.phoneNumber : message.from,
+      ...(userPhone && { userPhone }),
+      ...(waUserId && { userId: waUserId }),
       botPhoneNumberId: value.metadata.phone_number_id,
     },
+    // Keep the legacy userPhone-based identity whenever a phone number is available so existing
+    // conversations keep matching. Only opted-in users (no phone) are identified by the stable
+    // WhatsApp user_id.
+    discriminateByTags: userPhone ? ['botPhoneNumberId', 'userPhone'] : ['botPhoneNumberId', 'userId'],
   })
 
-  const { contacts } = value
-  const contact = contacts?.[0]
-  if (!contact) {
-    logger.forBot().warn('No contacts found, ignoring message')
-    return
-  }
+  // Keep the legacy phone-based identity (`wa_id`) as the user key whenever it's available so
+  // existing users keep matching instead of being recreated. Opted-in users (no `wa_id`) are
+  // identified by the stable WhatsApp user_id. The user_id is additionally stored on every user
+  // for forward reference.
+  const userIdentity = contact.wa_id ?? contact.user_id
   const { user } = await client.getOrCreateUser({
     tags: {
-      userId: contact.wa_id,
+      ...(userIdentity && { userId: userIdentity }),
+      ...(contact.user_id && { whatsappUserId: contact.user_id }),
+      ...(contact.wa_id && { number: contact.wa_id }),
+      ...(contact.profile?.username && { username: contact.profile.username }),
       name: contact.profile?.name,
     },
     name: contact.profile?.name,
diff --git a/integrations/whatsapp/src/webhook/handlers/reaction.ts b/integrations/whatsapp/src/webhook/handlers/reaction.ts
index d12e16dd21b..369728fa426 100644
--- a/integrations/whatsapp/src/webhook/handlers/reaction.ts
+++ b/integrations/whatsapp/src/webhook/handlers/reaction.ts
@@ -22,13 +22,21 @@ export const reactionHandler = async (reactionMessage: WhatsAppReactionMessage,
     return
   }
 
+  // Prefer the legacy phone identity so existing users keep matching; fall back to the stable
+  // user_id only for opted-in users with no phone number.
+  const reactingUserId = reactionMessage.from ?? reactionMessage.from_user_id
+  if (!reactingUserId) {
+    logger.forBot().warn('No user identifier found on reaction message, ignoring reaction')
+    return
+  }
+
   const previousReaction = message.tags.reaction
   const reactionHasChanged = currentReaction !== previousReaction
   if (previousReaction && reactionHasChanged) {
     await _handleReaction({
       message,
       reactionEventType: 'reactionRemoved',
-      userId: reactionMessage.from,
+      userId: reactingUserId,
       newReactionTagValue: undefined,
       eventReaction: previousReaction,
       ...props,
@@ -39,7 +47,7 @@ export const reactionHandler = async (reactionMessage: WhatsAppReactionMessage,
     await _handleReaction({
       message,
       reactionEventType: 'reactionAdded',
-      userId: reactionMessage.from,
+      userId: reactingUserId,
       newReactionTagValue: currentReaction,
       eventReaction: currentReaction,
       ...props,
diff --git a/integrations/whatsapp/src/webhook/handlers/sandbox.ts b/integrations/whatsapp/src/webhook/handlers/sandbox.ts
index 1f633f4bd3b..80012087b68 100644
--- a/integrations/whatsapp/src/webhook/handlers/sandbox.ts
+++ b/integrations/whatsapp/src/webhook/handlers/sandbox.ts
@@ -14,6 +14,7 @@ export const isSandboxCommand = (props: bp.HandlerProps): boolean => {
 }
 
 const NO_MESSAGE_ERROR = { status: 400, body: 'No message found in request' } as const
+const NO_PHONE_ERROR = { status: 400, body: 'No phone number found on message' } as const
 
 export const sandboxHandler: bp.IntegrationProps['handler'] = async (props: bp.HandlerProps) => {
   const { req } = props
@@ -39,6 +40,9 @@ const _handleJoinCommand = async (props: bp.HandlerProps) => {
   }
 
   const userPhoneNumber = message.from
+  if (!userPhoneNumber) {
+    return NO_PHONE_ERROR
+  }
   const botPhoneNumberId = value.metadata.phone_number_id
   const whatsapp = await getAuthenticatedWhatsappClient(client, ctx)
 
@@ -56,6 +60,9 @@ const _handleLeaveCommand = async (props: bp.HandlerProps) => {
   }
 
   const userPhoneNumber = message.from
+  if (!userPhoneNumber) {
+    return NO_PHONE_ERROR
+  }
   const botPhoneNumberId = value.metadata.phone_number_id
   const whatsapp = await getAuthenticatedWhatsappClient(client, ctx)
 
diff --git a/integrations/zendesk/integration.definition.ts b/integrations/zendesk/integration.definition.ts
index bda05f74d75..7457bab9940 100644
--- a/integrations/zendesk/integration.definition.ts
+++ b/integrations/zendesk/integration.definition.ts
@@ -6,7 +6,7 @@ import { actions, events, configuration, channels, states, user } from './src/de
 export default new sdk.IntegrationDefinition({
   name: 'zendesk',
   title: 'Zendesk',
-  version: '3.1.3',
+  version: '3.1.4',
   icon: 'icon.svg',
   description:
     'Optimize your support workflow. Trigger workflows from ticket updates as well as manage tickets, access conversations, and engage with customers.',
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 8be24db08f3..69f3c9f005b 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@botpress/cli",
-  "version": "6.8.3",
+  "version": "6.8.5",
   "description": "Botpress CLI",
   "scripts": {
     "build": "pnpm run build:types && pnpm run bundle && pnpm run template:gen",
diff --git a/packages/cli/src/command-implementations/dev-command.ts b/packages/cli/src/command-implementations/dev-command.ts
index 26b1eeb56c2..840db7f01cb 100644
--- a/packages/cli/src/command-implementations/dev-command.ts
+++ b/packages/cli/src/command-implementations/dev-command.ts
@@ -158,7 +158,15 @@ export class DevCommand extends ProjectCommand<DevCommandDefinition> {
 
     await this._runBuild()
     worker = await this._spawnWorker(env, port)
-    await this._deploy(api, httpTunnelUrl)
+
+    try {
+      await this._deploy(api, httpTunnelUrl)
+    } catch (thrown) {
+      if (worker.running) {
+        await worker.kill()
+      }
+      throw errors.BotpressCLIError.wrap(thrown, 'An error occurred while deploying the dev server')
+    }
 
     try {
       const watcher = await utils.filewatcher.FileWatcher.watch(
diff --git a/packages/common/src/entity-helpers/create-or-update-user.ts b/packages/common/src/entity-helpers/create-or-update-user.ts
index 1898c3ec777..b1f009649fa 100644
--- a/packages/common/src/entity-helpers/create-or-update-user.ts
+++ b/packages/common/src/entity-helpers/create-or-update-user.ts
@@ -24,21 +24,23 @@ export const createOrUpdateUser = async <
 ): Promise<Awaited<ReturnType<Client['createUser']>>> => {
   const { users: matchingUsers } = await props.client.listUsers({ tags: _getFilteredTags(props) })
 
-  if (matchingUsers.length > 1) {
+  const [firstUser, ...otherUsers] = matchingUsers
+  if (otherUsers.length > 0) {
     throw new sdk.RuntimeError('Multiple users found with the same discriminating tags')
   }
 
   type UserTags = keyof TIntegration['user']['tags']
-  const updateTags: Partial<Record<UserTags, string | null>> = { ...matchingUsers[0]!.tags, ...props.tags }
-  return (
-    matchingUsers.length === 1
-      ? await props.client.updateUser({
-          ...matchingUsers[0]!,
-          ...props,
-          tags: updateTags as Cast<typeof updateTags, Record<string, string | null>>,
-        })
-      : await props.client.createUser(props)
-  ) as Awaited<ReturnType<Client['createUser']>>
+
+  if (firstUser) {
+    const updateTags: Partial<Record<UserTags, string | null>> = { ...firstUser.tags, ...props.tags }
+    return (await props.client.updateUser({
+      ...firstUser,
+      ...props,
+      tags: updateTags as Cast<typeof updateTags, Record<string, string | null>>,
+    })) as Awaited<ReturnType<Client['createUser']>>
+  }
+
+  return (await props.client.createUser(props)) as Awaited<ReturnType<Client['createUser']>>
 }
 
 const _getFilteredTags = <TAGS extends client.User['tags']>({