See https://haskellstack.org/ for installation and upgrade instructions. **Changes since v2.5.1.1:** Behavior changes: * `stack repl` now always warns about GHCi problems with loading multiple packages. It also sets now proper working directory when invoked with one package. See [#5421](https://github.com/commercialhaskell/stack/issues/5421) * `custom-setup` dependencies are now properly initialized for `stack dist`. This makes `explicit-setup-deps` no longer required and that option was removed. See [#4006](https://github.com/commercialhaskell/stack/issues/4006) Other enhancements: * Nix integration now passes `ghcVersion` (in addition to existing `ghc`) to `shell-file` as an identifier that can be looked up in a compiler attribute set. * Nix integration now allows Nix integration if the user is ready in nix-shell. This gets rid of "In Nix shell but reExecL is False" error. * `stack list` is a new command to list package versions in a snapshot. See [#5431](https://github.com/commercialhaskell/stack/pull/5431) * Consider GHC 9.0 a tested compiler and remove warnings. * `custom-preprocessor-extensions` is a new configuration option for allowing stack to be aware of any custom preprocessors you have added to `Setup.hs`. See [#3491](https://github.com/commercialhaskell/stack/issues/3491) * Added `--candidate` flag to `upload` command to upload a package candidate rather than publishing the package. * Error output using `--no-interleaved-output` no longer prepends indentating whitespace. This allows emacs compilation-mode and vim quickfix to locate and track errors. See [#5523](https://github.com/commercialhaskell/stack/pull/5523) Bug fixes: * `stack new` now suppports branches other than `master` as default for GitHub repositories. See [#5422](https://github.com/commercialhaskell/stack/issues/5422) * Ignore all errors from `hi-file-parser`. See [#5445](https://github.com/commercialhaskell/stack/issues/5445) and [#5486](https://github.com/commercialhaskell/stack/issues/5486). * Support basic auth in package-indices. See [#5509](https://github.com/commercialhaskell/stack/issues/5509). * Add support for parsing `.hi`. files from GHC 8.10 and 9.0. See [hi-file-parser#2](https://github.com/commercialhaskell/hi-file-parser/pull/2). **Thanks to all our contributors for this release:** * Aaron Allen * Alexey Kuleshevich * Andreas Källberg * Domen Kožar * Emanuel Borsboom * Felix Yan * Jens Petersen * Kirill Zaborsky * Marcin Tolysz * Matt Audesse * Matthew Wraith * Michael Snoyman * Mike Pilgrem * Simon Michael