You can now set your working hours and let your teammates know when you're online. By default, new user profiles have a "flexible" working schedule, i.e., the working hours are not strictly defined. You can change this by going to your user profile and adjusting your working hours there:
Once set, your working hours will become visible on your Team Calendar and your calendar in your profile:
Our Slack bot has now your new working hours too, so if your colleagues try to reach you when you're offline, they'll get a friendly reminder: