When are Browser UI sites updated? 

Environment:

Browser User Interface (BUI) Updates

Resolution:

Browser User Interface is a single-version service that is updated without user impact. Agents can continue to work during deployment and can take the update at their leisure.  We consider the service continuous delivery and may perform updates as needed. 

Please see below for planned future updates and with release notes for past releases linked:

July Updates

Start dates and available details for each Update

Start Dates	Build	Release Notes	What's New
Non-production site deployment starts Jun 25th  Production site deployment starts Jul 9th	3.20.06.19-b0011	July 9th	n/a
Non-production site deployment starts Jul 9th  Production site deployment starts Jul 16th
Non-production site deployment starts Jul 16th  Production site deployment starts Jul 23rd
Non-production site deployment starts Jul 23rd  Production site deployment starts Jul 30th

June Updates

Start dates and available details for each Update

Start Dates	Build	Release Notes	What's New
Non-production site deployment starts May 28th  Production site deployment starts Jun 4th	3.20.5.22-b0012	June 4th	June 4th
Non-production site deployment starts Jun 4th  Production site deployment starts Jun 11th	3.20.05.29-b0008	June 11th	June 11th

All customers will receive these updates with zero down time.  At the time the update is pushed, all agents that are logged in will receive a message box that allows them to choose to accept the update or wait until they finish their current open work:

The first user that accepts the update for a specific interface will incur a cache hit, the cache for that interface will be re-created and that single user will experience a longer than usual refresh, but no other user of that interface will experience that lag.

Agent Browser User Interface is supported for the last five (5) Oracle Service Cloud releases for all customers.  Therefore to maintain Browser User Interface support, you must upgrade Oracle Service Cloud at least once a year. In order to leverage the latest and greatest of Agent Browser User Interface, we recommend you join the Auto Update Program and stay on the latest version of Oracle Service Cloud.

Other answers with Browser User Interface information:
Answer 6950: Raising Browser UI application issues
Answer 8173: Documentation for Supported Features in Browser User Interface
Answer 10506: Popular Answers about Browser User Interface (BUI)