Sitecore have provided the following table showing compatible browsers for each version:
The Importance of Browser Compatibility
We recommend that even if your Sitecore Content Management System is working well on a browser listed as incompatible, this could change in the next minor release and so should always be tested first.
From a user engagement perspective, the issues that occur with out-of-date browsers means that your editors could be affected detrimentally in their day-to-day activities. Any features that are either stunted or stop working due to the use of an incompatible browser could lead to painful (but often silently implemented) workarounds for your editing team which causes delays, adds unnecessary effort and complicates your normal processes.
Have a chat to us about evaluating the impact of any proposed updates. You can also read a bit more about this compatibility chart here
Contact us if you would like any further information on this.