Salesforce periodically releases updates that improve the performance, logic, and usability of Salesforce, but which can affect your existing customizations. When these updates become available, Salesforce lists them in Setup as Release Updates (formerly Critical Updates) and displays a message when administrators go to Setup.

To help keep you informed, we have created a master list of Salesforce Release Updates that also includes our recommendations for testing those within your sandbox environments before enabling those features to minimize risk. Based on our internal analysis, we have assigned each update a testing priority of high, medium, or low. We will update this support article before each major Salesforce release. 

Testing priority definitions

• Low: Salesforce functionality change might cause slight behavior changes in testing.
• Medium: Potential impact on Salesforce where functionality is being used in the org, may affect multiple processes, regression testing recommended
• High: Org security impacts, significant changes to org functionality, regression testing strongly recommended

Note: You can learn more about these updates by clicking the Update Name. 

Current Salesforce release updates with Provar testing recommendations for your organization