Send a message 15 minutes after a stage (e.g. CRM lead or project task) is changed.

Step 1: Enable Developer Mode

• Go to Settings → Activate Developer Mode (scroll to the bottom).
  

Step 2: Create a Server Action

• Go to Settings → Technical → Actions → Server Actions.
• Click Create.
• Fill in the details:
  • Name: Send message after stage change
  • Model: CRM Lead or Project Task (depending on what you want)
  • Action To Do: Python Code
• Add this code:

# Schedule a message after 15 minutes

send_time = fields.Datetime.now() + timedelta(minutes=15)

record.message_post(schedule_date=send_time, body="Stage was changed 15 minutes ago.")

Save the action.

Step 3: Create Automated Action (Trigger on Stage Change)

1. Go to Settings → Technical → Automation → Automated Actions.
2. Click Create.
3. Fill in:
   • Name: Stage Change Trigger
   • Model: CRM Lead (or your target model)
   • Trigger: On Update
   • Trigger Fields: stage_id
   • Action To Do: Execute a Server Action
   • Server Action: Choose the one you just created

If you're manually using "Scheduled Activity" or "message_post", the system doesn't show a "Scheduled Send Date" directly.

In the code, we are doing this:
send_time = fields.Datetime.now() + timedelta(minutes=15)

If you want to send a message 15 minutes after a stage change in Odoo, you will need to customize the workflow using code. 

For such customization's, feel free to contact us at info@srikeshinfotech.com.