Upgrading a SQLExpress 2008 instance to SQLExpress 2008 R2 version

Notice:

Microsoft recently released latest version of SQL Server, SQL Server 2008 R2, available in the Express edition as well you can download from Microsoft web site;
Supported Operating Systems are, as indicated in the release notes the following operating system: Windows 7; Windows Server 2003; Windows Server 2008; Windows Server 2008 R2;
this seems to exclude Windows XP from the available installation scenarios, but in the following experience we were able to install SQLExpress 2008 R2 on Windows XP service pack 2;
please be warned that Microsoft dropped Windows XP from the available OS and eventual use of such will result in an unsupported scenario.

Current goal: upgrading an existing SQLExpress 2008 with Advanced Services and related tools to 2008 R2 version.

The upgrade scenario is supported and we select the appropriate action in the SQL Server Installation Center dialog

After the traditional rules check we are prompted with the Und User License Agreement acceptance

and the SQL Server Support Files are checked and replaced or installed

We are then required to identify and select the instance to be upgraded in the Select Instance dialog

that correctly identifies current snapshot situation; we can further verify that snapshot at the file system level, where

The installation process starts verifying the Upgrade rules constraint

and finally proceeds with the standard SQL Server installation progress dialog

It took about 20 minutes to upgrade this virtual machine but we finally are rewarded with it's succesful completation

We upgraded therefore both the relational and the report server engines

The Add Remove system dialog reflects this upgrade

as the same does the File system

where brand news additional folders have been created for the relative upgraded engines, maintaining the older directories as well;
the original folders are now cleared in the binaries sense, and only log, data and the like folders are still active

Back to the installed management applications, we now have to connect via SQL Server Management Studio to the upgrade instance for further analysis

and we can immediately verify the management tool has been upgraded to SQL Server 2008 R2 as well.

Once connected we can start checking our Relational Engine state and behaviour

and we are reported with favourable info in a glance by the tool, indicating the instance is now at 10.50.1600 level.

An immediate check to one of our user database's properties confirm the availibility of the same, reporting the generic & large grane internal database compatibility level remains unchanged to SQL Server 2008 (100)

but please do not be tented to move such an upgraded database to a SQL Server 2008 base instance, as the internal metadata structures of the database has been change for sure; those internal changes can potentially affect instances at the very same version level but with different service pack levels, so moving databases to lower engine versions always is a bad and potentially dangerous practice.

Via the SQL Server Log viewer, the upgrade is re-confirmed as the initial server startup marks a log entry with it's version info

as does the tool, SQL Server Management Studio, reporting it's version info in it's About dialog

We can then start querying the instance for further confirmation via Transact-SQL specific statements

The Windows Services applet does not indicate any change as it is not devoted to, but we can check the health of our services which are up and running as before the upgrade

The SQL Server Configuration Manager tool has been modified as well since SQL Server 2008 release, and it's version reports it

as does the good ol' SqlCMD.exe command line tool, reporting the "2009.xx" major build number.

It's time to verify our applications, written for SQL Server 2008, still run without problems in the upgraded instance, and fortunately they do

and so do remote (non local) applications, indicating all network protocol, firewal and net based connectivity stuff has been not damaged by the upgrade process

The upgrade went very smooth and without particular problems, all precedent settings, at network protocols level as internal level like the ones accessible via SQL Server facets have been honoured and keep working;
The most relevant change can be, thougth, identified at the file system level, as an additional folder, MSSQL10_50.InstanceName has been added for the new binaries, but data files, log, ..., still remain in the older folder, as expected from the experience upgrading SQLExpress 2005 to 2008 version
this usually is not a problem, but keep in mind this feature.