The Microsoft Store version is updated by Windows. The setup-file version checks bandicam.com and offers the download inside the app.
Updates arrive automatically. To check now, open the Store app, choose Library, then Get updates. ZunShot does not download installers itself in this version.

ZunShot checks for a new version at start-up and shows a notice. You can also click ⓘ > Check for updates. The installer upgrades in place and keeps your settings.
ⓘ > About shows the version number, for example 27.13.x. Windows Settings > Apps shows Microsoft Store as the source for the Store version.