```ruby
class Charles < Cask
  url 'http://www.charlesproxy.com/assets/release/3.9/charles-proxy-3.9-applejava.dmg'
  homepage 'http://www.charlesproxy.com/'
  version '3.9'
  sha256 'a5d8c557fc97ed87dbf844cb1cf0d771c7a7d342c7c730cc22032995aa912d37'
  link 'Charles.app'
end
```

Update Charles to version 3.9.1
user
```ruby
class Charles < Cask
  url 'http://www.charlesproxy.com/assets/release/3.9.1/charles-proxy-3.9.1-applejava.dmg'
  homepage 'http://www.charlesproxy.com/'
  version '3.9.1'
  sha256 '0d85d3d589588a40dc45f337679b742670a12caba1b62a146ba6d878b7adb370'
  link 'Charles.app'
end
```
assistant