# castle v1.0.0 - Table of Contents > Runtime Hot-Code Upgrade support for Elixir ## Pages - [Castle](readme.md) - [Changelog](changelog.md) ## Modules - [Castle](Castle.md): Runtime hot-code upgrade support for Elixir releases. - Exceptions - [Castle.Error](Castle.Error.md): Raised when Castle refuses a command or `:release_handler` returns an error.