Will Branch still send event postbacks to ad networks for users who don't opt in under ATT?

Most network partners are configured to receive postbacks only for events that are attributed to them. Since Branch will not perform device-level attribution unless the user is opted in, these networks will not receive postbacks for opted-out users by definition.

If you have configured a network to receive postbacks for unattributed events, you may want to review your settings to ensure you're not sending data that could be considered 'ad tracking' under Apple's policy.