Dial-in restricted to paid subscriptions?

Hi! 

It looks like Zoom has repackaged dial-in to withdraw support of this feature from the Basic plan. 

I see that there's a list of phone numbers available to me in settings, and that for my location (the US) I need to be on a paid subscription to use even the toll number. 

When was this restricted? Is there any documentation of the change? 

Thank you!