There are many reasons why casks may be deprecated, disabled or removed. This document explains the differences between each method as well as explaining when one method should be used over another.
If a user attempts to install a deprecated cask, they will be shown a warning message but the install will proceed.
A cask should be deprecated to indicate to users that the cask should not be used and will be disabled in the future. Deprecated casks should continue to be maintained by the Homebrew maintainers if they continue to be installable. If this is not possible, they should be immediately disabled.
The most common reasons for deprecation are when the upstream project is deprecated, unmaintained or archived.
The `date` parameter should be set to the date that the deprecation period should begin, which is usually today's date. If the `date` parameter is set to a date in the future, the cask will not become deprecated until that date. This can be useful if the upstream developers have indicated a date when the project or version will stop being supported. Do not backdate the `date` parameter as it causes confusion for users and maintainers.
The `because` parameter can be a preset reason (using a symbol) or a custom reason. See the [Deprecate and Disable Reasons](#deprecate-and-disable-reasons) section below for more details about the `because` parameter.
An optional `replacement_formula` or `replacement_cask` parameter may also be specified to suggest a replacement formula or cask to the user. The value of the parameter is a string.
A cask should be disabled to indicate to users that the cask cannot be used and will be removed in the future. Disabled casks are those that can no longer be successfully installed.
Popular casks (e.g. have more than 300 [analytics installs in the last 90 days](https://formulae.brew.sh/analytics/cask-install/90d/)) should not be disabled without a deprecation period of at least six months unless they cannot be installed on any supported OS versions and the issue is unfixable (e.g. download URL no longer works and a mirror cannot be sourced).
Unpopular casks (e.g. have fewer than 300 [analytics installs in the last 90 days](https://formulae.brew.sh/analytics/cask-install/90d/)) can be disabled immediately for any of the reasons above, e.g. the upstream URL has been removed.
The `date` parameter should be set to the date that the reason for disabling came into effect. If there is no clear date but the cask needs to be disabled, use today's date. If the `date` parameter is set to a date in the future, the cask will be deprecated until that date (upon which the cask will become disabled).
The `because` parameter can be a preset reason (using a symbol) or a custom reason. See the [Deprecate and Disable Reasons](#deprecate-and-disable-reasons) section below for more details about the `because` parameter.
Similar to deprecated casks, an optional `replacement_formula` or `replacement_cask` parameter may also be specified for disabled casks to suggest a replacement formula or cask to the user. The value of the parameter is a string.
There are two ways to indicate the reason. The preferred way is to use a pre-existing symbol to indicate the reason. The available symbols are listed below and can be found in the [`DeprecateDisable` module](https://rubydoc.brew.sh/DeprecateDisable.html):
If these pre-existing reasons do not fit, a custom reason can be specified. Such reasons should be written to fit into the sentence `<cask> has been deprecated/disabled because it <reason>!`.
A well-worded example of a custom reason would be:
```ruby
# Warning: <cask> has been deprecated because it has unresolved CVEs!