# How to test Windows Phone app upgrades

Properly testing app upgrades on Windows Phone is not as straightforward as it could be. When you deploy a XAP from the IDE or with the XapDeploy tool the build system will evaluate whether an incremental update is possible or if a full redeploy is required.  A full redeploy will remove all of the app’s IsolatedStorage and make testing upgrades impossible unless we use the ISETool.

## Deploy the current version of the app

For this step you can install the current version of the app any way you want.

Use the app to populate its isolated storage.  As a developer you should know what is cached by your application so use it in such a way that the isolated storage is fully populated.

ISETool.exe is located in your SDK and you will find it in a path similar to this:

C:\Program Files (x86)\Microsoft SDKs\Windows Phone\v8.0\Tools\IsolatedStorageExplorerTool\ISETool.exe

For the sake of brevity I will omit the full path in the rest of the post.  To backup your isolated storage use the following command:

ISETool.exe ts <device> <product id>"C:\path\to\backup\folder"
• Replace <device> with “xd” if you are backing up an emulator or “de” if you are backing up a device.
• Replace <product id> with the ProductID of your app as defined in WMAppManifest.xml

After the command completes verify that the data has been backed up to the path you specified.

## Install the new version

When installing the new version it is important to use the XapDeploy tool because it will install the new version without starting it, giving us a chance to restore the settings first.  This tool is a graphical one so just select the new xap and the device or emulator to install it to.

ISETool.exe rs <device> <product id> "C:\path\to\backup\IsolatedStore"