From Natfka's blog:
HH Weekender 2017
Secutarii are a new branch of the Taghmata army list. Can never have
automata in the detachement; big focus on infantry and transports.
Secutarii Psiloi, fast attack.
Secutarii Hetairoi, elite.
Secutarii Hypaspists, elite.
Secutarii Heleposis, open topped transport (20 capacity).
You can find more information at his blog post here:
What do you think? And if true, what do you hope to see as part of this expansion?