We will be pushing a Zuora for Salesforce maintenance release (Quotes 9.22) to all 9.21+ Sandbox orgs after 6 pm Pacific on March 23rd, 2020.
The push upgrade to all 9.21+ Production orgs will be scheduled for after 6 pm Pacific on March 30th, 2020.
This upgrade will be deployed to orgs on Quotes version 9.21 and 9.21.1, and is inclusive of changes in Quotes 9.21.1. Quotes 9.22 will include minor fixes, as well as the ability to authorize additional Zuora REST services used by upcoming and limited availability features.
Release Notes are available with details, along with updates to authorization setup.