Last year, Astro launched its Astrobot Slack app, which let users manage their emails and check their Office 365 or Google calendars from within Slack. It also allowed them to do one search to pull up results from both Slack and email. "As we explored with Slack how to bring together messaging, email and calendar, it became evident that we would have the biggest impact on workplace communications and realize our original vision by joining Slack," the company said.

The bad news about the acquisition for Astro users is that the company is shutting down its Mac, iOS, Android, Alexa and Slack apps. Astro is no longer taking new users and existing ones will lose access on October 10th.