First, check what version you have by going to your You tab. At the bottom of this page, you should see the version number (ex. v.527.0)
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Depending on if you have iOS or Android,
you can update in the App Store or Google Play
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Just check for Updates > Heja
Important:
In the App Store sometimes you will see a Open button instead of an Update button. In this case please press the Heja app icon beside the button and the button will change to Update