FreedomPop: account update

I logged in to do something with a FreedomPop (basic LTE free) plan today. There is this notice on the dashboard:

IMPORTANT NOTICE
System updates resulting in service
interruptions planned for
Wed. 2/26/2020@10-10:30 PM PST.
After this update, please click below and
follow the quick & easy steps
to refresh your settings.
"COMPLETE UPDATE!" (button)

I did not follow the suggested action at this point. Service still works on the line at this point, so I'll catch up to that task later.

I don't know what this is about. But we can be pretty sure it's not about enabling cellular voice, since the Unreal thread indicates they have to send out new SIM cards to enable that. It might be something to do with a profile setting update, etc, or a redirect to change APN settings, or ?

Similar message at Unreal

IMPORTANT NOTICE:
System updates resulting in service
interruption planned for
Wed. 2/26/2020 @ 10:00 - 10:30 PM PST.
After this update, please
follow the quick & easy steps
at APN Configuration | UNREAL Mobile
to refresh your settings.

I had to change my APN from unreal.com.attz to fp.com.attz (I'm on the VOIP SIM).

On the configuration page it shows 2 options "GSM SIM ICCID starts with 89011**" and "Premium LTE SIM ICCID starts with 89014**"
So there really are different sims for different service types.