# Release 15.09 (“Dingo”, 2015/09/??)

In addition to numerous new and upgraded packages, this release has the following highlights:

- The Haskell packages infrastructure has been re-designed from the ground up. NixOS now distributes the latest version of every single package registered on Hackage, i.e. well over 8000 Haskell packages. Further information and usage instructions for the improved infrastructure are available at https://nixos.org/wiki/Haskell. Users migrating from an earlier release will find also find helpful information below, in the list of backwards-incompatible changes.

- Users running an SSH server who worry about the quality of their `/etc/ssh/moduli` file with respect to the vulnerabilities discovered in the Diffie-Hellman key exchange can now replace OpenSSH's default version with one they generated themselves using the new `services.openssh.moduliFile` option.

When upgrading from a previous release, please be aware of the following incompatible changes:

- `sshd` no longer supports DSA and ECDSA host keys by default. If you have existing systems with such host keys and want to continue to use them, please set

      system.stateVersion = "14.12";

  (The new option `system.stateVersion` ensures that certain configuration changes that could break existing systems (such as the `sshd` host key setting) will maintain compatibility with the specified NixOS release.)

- `cron` is no longer enabled by default, unless you have a non-empty `services.cron.systemCronJobs`. To force `cron` to be enabled, set `services.cron.enable = true`.

- Nix now requires binary caches to be cryptographically signed. If you have unsigned binary caches that you want to continue to use, you should set `nix.requireSignedBinaryCaches = false`.

- Steam now doesn't need root rights to work. Instead of using `*-steam-chrootenv`, you should now just run `steam`. `steamChrootEnv` package was renamed to `steam`, and old `steam` package -- to `steamOriginal`.

- CMPlayer has been renamed to bomi upstream. Package `cmplayer` was accordingly renamed to `bomi`

- Atom Shell has been renamed to Electron upstream. Package `atom-shell` was accordingly renamed to `electron`

- Elm is not released on Hackage anymore. You should now use `elmPackages.elm` which contains the latest Elm platform.

- The CUPS printing service has been updated to version `2.0.2`. Furthermore its systemd service has been renamed to `cups.service`.

  Local printers are no longer shared or advertised by default. This behavior can be changed by enabling `services.printing.defaultShared` or `services.printing.browsing` respectively.

- The VirtualBox host and guest options have been moved/renamed more consistently and less confusing to be now found in `virtualisation.virtualbox.host.*` instead of `services.virtualboxHost.*` and `virtualisation.virtualbox.guest.*` instead of `services.virtualboxGuest.*`.

- Haskell packages can no longer be found by name, i.e. the commands `nix-env -qa cabal-install` and `nix-env -i ghc` will fail, even though we do ship both `cabal-install` and `ghc`. The reason for this inconvenience is the sheer size of the Haskell package set: name-based lookups such as these would become much slower than they are today if we'd add the entire Hackage database into the top level attribute set. Instead, the list of Haskell packages can be displayed by

      nix-env -f "<nixpkgs>" -qaP -A haskellPackages

  and packages can be installed with:

      nix-env -f "<nixpkgs>" -iA haskellPackages.cabal-install

- Previous versions of NixOS came with a feature called `ghc-wrapper`, a small wrapper script that allows GHC to transparently pick up on libraries installed in the user's profile. This feature has been deprecated; `ghc-wrapper` was removed from the distribution. The proper way to register Haskell libraries with the compiler now is the `haskellPackages.ghcWithPackages` function. https://nixos.org/wiki/Haskell provides much information about this subject.

- All Haskell builds that have been generated with version 1.x of the `cabal2nix` utility are now invalid and need to be re-generated with a current version of `cabal2nix` to function. The most recent version of this tool can be installed by running `nix-env -i cabal2nix`.

- The `haskellPackages` set in Nixpkgs used to have a function attribute called `extension` that users could override in their `~/.nixpkgs/config.nix` files to configure additional attributes, etc. That function still exists, but it's now called `overrides`.

- The OpenBLAS library has been updated to version `0.2.14`. Support for the `x86_64-darwin` platform was added. Dynamic architecture detection was enabled; OpenBLAS now selects microarchitecture-optimized routines at runtime, so optimal performance is achieved without the need to rebuild OpenBLAS locally. OpenBLAS has replaced ATLAS in most packages which use an optimized BLAS or LAPACK implementation.

- The `phpfpm` is now using the default PHP version (`pkgs.php`) instead of PHP 5.4 (`pkgs.php54`).

- The `locate` service no longer indexes the Nix store by default, preventing packages with potentially numerous versions from cluttering the output. Indexing the store can be activated by setting `services.locate.includeStore = true`.

- The Nix expression search path (`NIX_PATH`) no longer contains `/etc/nixos/nixpkgs` by default. You can override `NIX_PATH` by setting `nix.nixPath`.

The following new services were added since the last release:

- `brltty`

- `marathon`

- `tvheadend`

Other notable improvements:

- The nixos and nixpkgs channels were unified, so one can use `nix-env -iA nixos.bash` instead of `nix-env -iA nixos.pkgs.bash`. See the commit for details.