Telstra warns older iPhones may be unable to connect to Triple Zero
www.abc.net.au
Customers are advised to delay software updates on affected devices and find alternative ways to communicate if needed.

In short:

Some older iPhones, including iPhone 8, 8 Plus and X, are unable to connect to Telstra’s network after a recent Apple update, the telco says.

The nationwide issue affects calls to all numbers, including emergency calls to Triple Zero (000).

Customers are advised to delay software updates on affected devices and find alternative ways to communicate if needed.