AT&T has experienced more than one massive customer data breach and yet they still want to "update" to "more cost-effective" bullshit. Here's a reminder that the "more cost-effective" bullshit isn't only hackable but it's also not covered by the standard Common Carrier laws which I'm sure AT&T wants to evade, big-time.
Unless and until fiber is a direct replacement for copper AND is covered by Common Carrier Law, keep your copper.