My mobile number has transferred to a new SIM card in a new iPhone but I'm still getting text / iMessage messages on the old iPhone

To resolve, remove your phone number from the iMessage app on the old iPhone and register it on the new iPhone

1. On the old iPhone go to the Settings app
2. Select Messages (halfway down)
3. If you see the number you're transferring under iMessage select Send & Receive
4. Untick the number
5. In the popup Remove Number from iMessage message, select Remove
6. iMessage should now be disabled on your old iPhone
7. On the new iPhone go to the Settings app
8. Select Messages (halfway down)
9. Enable iMessage or select Send & Receive if already enabled
10. If the number shown is your temporary 3 Mobile number (starting 07311 310…) untick that number
11. Re-enable iMessage and the number should change to the number you're transferring.
12. Test you are now receiving text messages on the correct iPhone.
13. If your Apple iMessages and text messages have not restored to your new iPhone, see:
    How do I transfer Apple iMessages and text messages from one iPhone to another?