Version 4 supported
This version of Silverstripe CMS is still supported though will not receive any additional features. Go to documentation for the most recent stable version.


You'll need to go through your codebase to remove references to deprecated APIs and update your project logic.

Major releases of Silverstripe CMS introduce many API changes. They include a deprecation message that will either tell you:

  • to simply use a different yet equivalent API instead, or
  • the API in question has no replacement. This is usually for API that was mostly irrelevant.

Enabling deprecation warnings

To enable deprecation warnings, set the SS_DEPRECATION_ENABLED environment variable in your project's .env file.

If the SS_DEPRECATION_ENABLED environment variable is set, this takes precedence over use of the Deprecation::enable() static method.

Alternatively, add the following line to your project's app/_config.php.

Deprecation warnings will only ever show if your SS_ENVIRONMENT_TYPE is set to dev.

Once you have resolved all of the deprecation warnings you can, it is recommended to turn off deprecation warnings again.

Not all API that gets deprecated will have an equivalent replacement API in that same major version; some of the API is only available from the next major release. A good example of this is the upgrade for what powers the SilverStripe\Control\Email\Email class from swiftmailer in CMS 4 to symfony/mailer in CMS 5. In these cases, you'll need to upgrade to the new major version before you can access the replacement API.

Some code that has been deprecated with no immediate replacement will not emit deprecation notices by default. If you wish to also see notices for deprecated code with no immediate replacement, add the following line to you project's app/_config.php file. Note that this will also emit deprecation notices for usages of the deprecated code inside core modules.


How to view deprecation warnings

By default, deprecation warnings will be emitted to the error logger, and will be output at the end of CLI responses. They will not be included in HTTP responses by default.

Viewing deprecation warnings in the logs

Deprecation warnings are output to the same error logger as all other warnings and errors. You will need to make sure you have a logging handler attached to the default Psr\Log\LoggerInterface or Psr\Log\LoggerInterface.errorhandler singletons. For example, to log to a file you can add this to your yml configuration:

    class: Monolog\Handler\StreamHandler
      - "var/www/silverstripe.log"
      - "warning" # warning is the level deprecation warnings are logged as
      ErrorLogFileHandler: [ pushHandler, [ '%$ErrorLogFileHandler' ] ]
The log file path must be an absolute file path, as relative paths may behave differently between CLI and HTTP requests. If you want to use a relative path, you can use the SS_ERROR_LOG environment variable to declare a file path that is relative to your project root:


You don't need any of the yaml configuration above if you are using the SS_ERROR_LOG environment variable - but you can use a combination of the environment variable and yaml configuration if you want to configure multiple error log files.

You will also need to make sure the user running the php process has write access to the log file, wherever you choose to put it.

See Configuring error logging to learn about other ways you can handle error logs.

Deprecation warnings in your browser

Deprecation warnings won't be output to HTTP responses by default because it can be difficult to parse and collate information this way, and deprecation warnings in XHR/AJAX responses can result in unexpected behaviour in some situations. That said, you can choose to enable this output.

Deprecation warnings can be set to output in HTTP responses by setting SS_DEPRECATION_SHOW_HTTP to a truthy value in your .env file.

If the SS_DEPRECATION_SHOW_HTTP environment variable is set, this takes precedence over use of the Deprecation::setShouldShowForHttp() static method.

Alternatively, add the following line to your project's app/_config.php.


Note that the output for this won't be very easy to read. You might prefer instead to install lekoala/silverstripe-debugbar as a dev dependency. Deprecation warnings will be logged in the "messages" tab of the debugbar.

The debugbar will not show you any deprecation warnings that are triggered from XHR/AJAX requests or which are triggered after the middleware has finished generating the debugbar for the response.

Deprecation warnings in the CLI

Deprecation warnings are output for CLI responses by default (assuming they're enabled in general). The warnings are always output at the end of the request, so you don't have to go looking through the output for them. You might want to disable outputting these warnings in CLI responses if, for example, you need to validate the output via code and don't want to add special cases for deprecation warnings.

You can suppress deprecation warnings from CLI output by setting SS_DEPRECATION_SHOW_CLI to a falsy value in your .env file.

If the SS_DEPRECATION_SHOW_CLI environment variable is set, this takes precedence over use of the Deprecation::SS_DEPRECATION_SHOW_CLI() static method.

Alternatively, add the following line to your project's app/_config.php.