As part of their ongoing support of Warhammer 40k, Games Workshop have dripfeeding new info about the new updates coming to various armies. The current Nachmund season has shown new things coming down the line for the Imperium and Chaos. The Aeldari are getting an update for the first time in a long time. Then there is the highly technologically advanced mechs and battlesuits of the Tau Empire, the new details of their upcoming codex Games Workshop was happy to share.
In an official Warhammer Community post, Games Workshop highlighted the newest addition to Warhammer 40k's Tau. In the lore, planets that have been colonized by the Tau are collectively referred to as septs, which are culturally diverse but still a part of the greater Tau Empire. This is important because you can now choose one of six of these major septs to represent where your Tau army came from, and all of the influences that come with it. Each of these six major septs will have you gain a sept tenet, a Warlord Trait, a Signature System Relic, and an exclusive Stratagem, representing the character of the worlds they live on.
The post goes on to explain some of these new benefits for the Tau. The Dal'yth sept focuses on trade and commerce, a true rarity in the world of Warhammer 40k, which lends its armies a greater appreciation for the auxiliaries that supplement their ranks, and they excel in training Kroot and Vespid forces to use the Fire Caste’s powerful Tactical Philosophies. In turn, their Hunter Cadres pick up expert fieldcraft skills from alien comrades. Alternatively, the Sa'cea sept focuses more on strategically capturing and locking down key terrain and locations. As for Relics, one of the ones, Vectored Manoeuvring Thrusters, comes from the T'au sept. It helps give battlesuits a lot more mobility on the battlefield.
But if you don't like any of the six major septs for your Tau army, you still have options. In a dark sci-fi universe as vast as Warhammer 40k, there are tons of smaller factions, splinter groups, chapters, and armies all running about, and the Tau Empire is no different. You can choose to play as a minor sept, at which point you have the chance to pick and choose certain sept tenets and strategems for yourself. There are limitations based the various sectors of the empire laid out, but by GW's own admission, there are roughly 100 different potential combinations.
The latest Tau codex for Warhammer 40k still has no concrete release date.