Mobile operators are directly reaching out to customers still reliant on the 3G network before it shuts down

Pre-call announcements are being sent to people with devices that need updating, with instructions on next steps.

Telecommunications Forum programme manager Clare Dobson says updating's essential.

She says older devices won't work after the 3G shutdown, and even 111 calls won't connect.

Mobile operators will begin shutting down their 3G networks at the end of the year.