First, check if the problem was with your download. Delete the downloaded file (its location will be pointed out right under the Actual shasum line) and try again.
If the problem persists, the cask must be outdated. It’ll likely need a new version, but it’s possible the version has remained the same (happens occasionally when the vendor updates the app in place).
- Go to the vendor’s website (
brew cask home {{cask_name}}).- Alternatively, if it has an
appcast, read that (curl "$(brew cask _stanza appcast {{cask_name}})").
- Alternatively, if it has an
- Find out what the latest version is. It will likely be expressed in the URL used to download it.
- Take a look at the cask’s version (
brew cask _stanza version {{cask_name}}) and verify it is indeed outdated. If it is:
Help us by submitting a fix. If you get stumped, open an issue explaining your steps so far and where you’re having trouble.