LTE-M (LTE Cat-M1)
Updated
LTE-M is a low-power version of 4G LTE for IoT, standardised by 3GPP in Release 13. It uses a 1.4 MHz channel, supports devices on the move and handovers between cells, and can carry voice over LTE. It reaches further indoors than standard LTE while using less power.
In practice
LTE-M suits trackers, wearables and meters that move or need moderate data rates; check that the networks of each country support it before choosing a module.