This tutorial describes how to choose the exact version of Pega Mobile Client™ with which the mobile app is built in Pega Platform™, in the Channels and interfaces tab. Setting the version can help you avoid compatibility issues with the devices that are used in your organization.

1. Determine which version of Pega Mobile Client was used to build your current mobile app:
   1. Install your mobile app on the device.
   2. In your app, click Menu > Settings > System info.
   3. In the HC version field, note the Pega Mobile Client version number.
2. Lock the version of Pega Mobile Client to be used to build your new mobile app:
   1. In Dev Studio, use the search field to find the .pyHCBuildVersion Declare Expression rule.
   2. In the Save as list, click Specialize by class or ruleset.
   3. In Add to ruleset, select the ruleset for your mobile app.
   4. Click Create and open to open the .pyHCBuildVersion rule that is specific to your app.
   5. Complete the condition in the declare expression by setting the value of HCBuildVersion to the Pega Mobile Client version that you noted in step 1c.
      You can enter either the full version number (for example, 6.21.1.5), or just the prefix (for example, 6.21). Pega Platform always selects the most exact version number. If several sub-versions match the defined pattern, it selects the newest one.
   6. Click Save