Zoom launched a 90-day initiative in early April to address and proactively fix issues related to security. As part of that initiative, Zoom has released a required update to all versions of the Zoom desktop client.
All members of the U‑M community using Zoom should ensure they have updated to the latest Zoom client by Saturday, May 30, or they will be unable to connect to meetings scheduled after that date.
Please see this Zoom Help Center article for instructions on updating your client: https://support.zoom.us/hc/en-us/articles/201362233-Where-Do-I-Download-The-Latest-Version-