Every 6 weeks, Microsoft pushes a new stable build of their new Edge browser, and today the update takes it to version 88.0.705.63.
This update appears to be primarily a security update meant to address CVE-2021-21148, a Chromium bug which is being exploited in the wild.
Full details of the exploit have not been released yet to allow users to update their browser.
The update to Edge Stable is rolling out over several days, but users are recommended to force the update by going to Menu > Help and Feedback > About Edge.
You can download the new Edge browser at Microsoft here.