Recently I ran into an issue with slimapp where tests on PHP 7.1 were failing because of a Generic.PHP.DeprecatedFunctions.Deprecated warning. This project is currently maintaining PHP 5.5 compatibility and thus can't update to a newer version of mediawiki/mediawiki-codesniffer where the Generic.PHP.DeprecatedFunctions.Deprecated sniff has already been removed. The 19.x branch is the last place where we support PHP 5.5. My quick fix was to disable the sniff in local config, but @Legoktm thought that it would be worth updating generally for other PHP 5.5 consumers.