On October 1st, 2017 a change in PSTN Conferencing for Office 365 is coming to a tenant near you.
PSTN Conferencing will in the future, as a supplement to the well-known monthly subscription, also be available as Audio Conferencing pay-per-minute feature for E1, E3 and VL customers.
The most important notes are:
No monthly PSTN Conferencing subscription per users
Toll and toll-free inbound calls are charged on a per-minute basis
All outbound calls are charged on a per-minute basis
Available to enterprise E1, E3 and VL customers
This new feature will be a very interesting change for enterprises there are not using E5 license already. Especially if the E3 users only uses the PSTN Conferencing on a non-regular basis.
If a user has a PSTN Conferencing license (add-on or included) all toll inbound calls and outbound domestic (domestic to the user location) is included in the subscription fee. The add-on subscription license is $4.00 per user monthly.