Having worked in this space in another life I would suggest the IP core upgrade would not bring down the voice (3g 4g 5 g) and sms networks. Totally separate to internet and IT systems. I can only suggest that the route choosen to disconnect and rebuild was selected as a quicker scenario to rebuild (with everything down) instead of rebuilding and re configuring with active systems in flight.
Networks can be kept active but would loose billing and usage data collated through the IP core.
Cannot see this being done in band as that was not normal practice so that piece needs a response from the company if indeed that scenario was a choosen approach.
TLS Price at posting:
$3.83 Sentiment: Hold Disclosure: Held
A personalised tool to help users track selected stocks. Delivering real-time notifications on price updates, announcements, and performance stats on each to help make informed investment decisions.
(20min delay)