```ruby
cask :v1 => 'bettertouchtool' do

  if MacOS.release <= :snow_leopard
    version '0.939'
    sha256 'fad5e9d36259c379bdb33188cf15d179fd9ff73023035c98f5734e7e3e13bb75'

    # bettertouchtool.com is the official download host per the vendor homepage
    url "http://bettertouchtool.net/btt#{version}.zip"
  else
    version '1.19'
    sha256 'a246cf37c0fe5142ebc52fb99c54ab3ed2e261dccbf45b486575139fe1184675'
    url "http://boastr.net/releases/btt#{version}.zip"
  end

  appcast 'http://appcast.boastr.net'
  name 'BetterTouchTool'
  homepage 'http://boastr.net/'
  license :gratis

  app 'BetterTouchTool.app'

  zap :delete => [
                  '~/Library/Preferences/com.hegenberg.BetterTouchTool.plist',
                  '~/Library/Application Support/BetterTouchTool',
                 ]
end
```

Update Better Touch Tool to 1.20
user
```ruby
cask :v1 => 'bettertouchtool' do

  if MacOS.release <= :snow_leopard
    version '0.939'
    sha256 'fad5e9d36259c379bdb33188cf15d179fd9ff73023035c98f5734e7e3e13bb75'

    # bettertouchtool.com is the official download host per the vendor homepage
    url "http://bettertouchtool.net/btt#{version}.zip"
  else
    version '1.20'
    sha256 'd1e03b7f8210e5d36ea9ae1ce4afe0eecd29f5c768b8ab1245e6882bde3b98f2'
    url "http://boastr.net/releases/btt#{version}.zip"
  end

  appcast 'http://appcast.boastr.net'
  name 'BetterTouchTool'
  homepage 'http://boastr.net/'
  license :gratis

  app 'BetterTouchTool.app'

  zap :delete => [
                  '~/Library/Preferences/com.hegenberg.BetterTouchTool.plist',
                  '~/Library/Application Support/BetterTouchTool',
                 ]
end
```
assistant