Sql-server – SELECT SERVERPROPERTY(‘ProductUpdateLevel’) SHOWING NULL

A few things you'll want to watch out for:

• Changes to memory manager mean some changes to some dynamic management views - https://sqlblog.org/2011/01/08/sql-server-v-next-denali-changes-to-performance-counters

• fn_virtualfilestats no longer takes -1 for parameters - https://sqlblog.org/2011/06/28/sql-server-v-next-denali-breaking-change-to-fn_virtualfilestats

• you may no longer be able to identify system databases simply by DB_ID between 1and 4 - https://sqlblog.org/2011/07/08/sql-server-v-next-denali-breaking-change-to-system-databases-database_id-db_id

• Temp tables now get negative object IDs, so make sure you don't have code that checks for object id > 0 - https://sqlblog.org/2010/11/09/sql-server-v-next-denali-breaking-change-to-temp-tables

• sys.dm_exec_sessions has a new column, authenticating_database_id

For an official list (it doesn't include all of the above items, and there may be others that aren't coming to mind):

http://technet.microsoft.com/en-us/library/ms143179(v=SQL.110).aspx

You may also want to check the discontinued features page:

http://technet.microsoft.com/en-us/library/ms144262

And also run the Upgrade Advisor against your instance, this is exactly what it's for:

http://technet.microsoft.com/en-us/library/ms144256.aspx

You have installed a new instance of SQL Server, so you need to change the way you connect to that new instance.

Previously, you had a default instance, so connecting using any of these in the Server name: box would work fine:

localhost
.
127.0.0.1
<any_local_IP>
<your_machine_name>
<your_FQDN>

Now that you have installed a new instance of SQL Server, you need to reference that instance name as part of the connection string, so any of the above need to become the following:

localhost\MSSQLSERVER14
.\MSSQLSERVER14
127.0.0.1\MSSQLSERVER14
<any_local_IP>\MSSQLSERVER14
<your_machine_name>\MSSQLSERVER14
<your_FQDN>\MSSQLSERVER14