Genshin Impact 3.5 will launch later today, February 28, for many Western players, alongside the debut banner for the new five-star character Dehya.
The update is technically scheduled for tomorrow, March 1, but should launch later today around 7pm PT / 10pm ET following four or five hours of maintenance downtime. Genshin Impact update maintenance often ends 30 minutes to an hour ahead of schedule.
Dehya is the star of update 3.5 – despite pre-release blowback over her perceived design and balance flaws – but it's important to remember that she will be added to the standard banner character pool with the launch of update 3.6. In other words, even if you don't roll for Dehya on her 3.5 banner, you'll probably end up getting her eventually just by rolling for other limited characters (and inevitably losing some 50/50 pities) or cashing in standard wishes. That said, her release banner will likely be the only way to ever 100% guarantee that you obtain her, so spend your primogems as you see fit.
Dehya will debut alongside the first rerun for Cyno. The four-star characters on their banners are Collei, Barbara, and Bennett. Barbara gained new utility with the release of Dendro and Bennett is still one of the best units in the entire game, but Collei is generally behind the Dendro version of the Traveler, so she's less desirable.
The second half of update 3.5 will feature Ayaka and Shenhe, two Cryo icons inexplicably paired with the new four-star character Mika, who's been pitched as a physical damage support explicitly designed for the notably absent Eula.
Hoyoverse has already revealed Baizhu and Kaveh for Genshin Impact update 3.6.