```ruby
class Lyn < Cask
  version '1.3.7'
  sha256 '5a1b937e4226dc0cb69f187296821410a150ac0994fea629e789f84baecb7c28'

  url 'http://www.lynapp.com/downloads/Lyn-1.3.7.dmg'
  appcast 'http://www.lynapp.com/lyn/update.xml'
  homepage 'http://www.lynapp.com/'

  link 'Lyn.app'
end
```

Update Lyn app to latest version 1.5.2
user
```ruby
class Lyn < Cask
  version '1.5.2'
  sha256 'a4200b35eb4e51c3932a9e7cd40e1be3291a26921da350d396d337fa667798f6'

  url 'http://www.lynapp.com/downloads/Lyn-1.5.2.dmg'
  appcast 'http://www.lynapp.com/lyn/update.xml'
  homepage 'http://www.lynapp.com/'

  link 'Lyn.app'
end
```
assistant