The service pack was released a few weeks ago and is available at here.  It will require you to log in to MyCitrix to download it.

XD Service Pack 1 improvements and known issues document is available here.

Its highly recommend that you install the service pack update with the same account that installed the product. If you install it with a different account that doesn’t have an account to the database, you might see the following error Database User Not Found when performing the database schema upgrade. To avoid this condition, simply use the original account or give the service pack installation account DBO rights to the database

Database user not found

SQL Script to provide DBO rights

create login [MyDomain\UserAccount] from windows
Use CitrixXenDesktopDB
create user [MyDomain\UserAccount] with default_schema=dbo
sp_addrolemember ‘db_owner’,[MyDomain\UserAccount]

You can confirm the database was successfully updated by running XDDBDiag and verifying the schema version is set to 5.1.00

Example

XenDesktop Site summary:

Schema version: ……………. 5.1.0.0