Will I lose my tasks if I upgrade from trial to paid?

We would however advise you delete the Trial version before making a purchase on the store (or before installing it from the app store). This is because although the App Store makes an attempt to overwrite the trial version, it does not always succeed in properly installing over the old version. So you may launch the app to find it’s still in ’Trial mode’. Deleting the trial version ensures you’ve downloaded the full version directly from the Mac App Store.