This is not a new version!!!!
IEEE1588-2018 will be a set of new, optional features asked for by particular industry groups:
Provides a way of monitoring the status and time at a slave clock
Slave reports a TLV containing the timing of event messages relative to the slave local clock time
Interfaces PTP to timing ports on other technologies
Note: Diagram taken from Doug Arnold's presentation at ITSF 2017 (Meinberg)
Mixed Multicast/Unicast Operation
Modular Transparent Clocks