- The following changes apply if the `stateVersion` is changed to 17.09 or higher. For `stateVersion = "17.03"` or lower the old behavior is preserved.

  - The `postgres` default version was changed from 9.5 to 9.6.

  - The `postgres` superuser name has changed from `root` to `postgres` to more closely follow what other Linux distributions are doing.

  - The `postgres` default `dataDir` has changed from `/var/db/postgres` to `/var/lib/postgresql/$psqlSchema` where \$psqlSchema is 9.6 for example.

  - The `mysql` default `dataDir` has changed from `/var/mysql` to `/var/lib/mysql`.

  - Radicale's default package has changed from 1.x to 2.x. Instructions to migrate can be found [ here ](http://radicale.org/1to2/). It is also possible to use the newer version by setting the `package` to `radicale2`, which is done automatically when `stateVersion` is 17.09 or higher. The `extraArgs` option has been added to allow passing the data migration arguments specified in the instructions; see the `radicale.nix` NixOS test for an example migration.

- The `aiccu` package was removed. This is due to SixXS [ sunsetting](https://www.sixxs.net/main/) its IPv6 tunnel.

- The `fanctl` package and `fan` module have been removed due to the developers not upstreaming their iproute2 patches and lagging with compatibility to recent iproute2 versions.

- Top-level `idea` package collection was renamed. All JetBrains IDEs are now at `jetbrains`.

- `flexget`'s state database cannot be upgraded to its new internal format, requiring removal of any existing `db-config.sqlite` which will be automatically recreated.

- The `ipfs` service now doesn't ignore the `dataDir` option anymore. If you've ever set this option to anything other than the default you'll have to either unset it (so the default gets used) or migrate the old data manually with

  ```ShellSession
  dataDir=<valueOfDataDir>
  mv /var/lib/ipfs/.ipfs/* $dataDir
  rmdir /var/lib/ipfs/.ipfs
  ```

- The `caddy` service was previously using an extra `.caddy` directory in the data directory specified with the `dataDir` option. The contents of the `.caddy` directory are now expected to be in the `dataDir`.

- The `ssh-agent` user service is not started by default anymore. Use `programs.ssh.startAgent` to enable it if needed. There is also a new `programs.gnupg.agent` module that creates a `gpg-agent` user service. It can also serve as a SSH agent if `enableSSHSupport` is set.

- The `services.tinc.networks.<name>.listenAddress` option had a misleading name that did not correspond to its behavior. It now correctly defines the ip to listen for incoming connections on. To keep the previous behaviour, use `services.tinc.networks.<name>.bindToAddress` instead. Refer to the description of the options for more details.

- `tlsdate` package and module were removed. This is due to the project being dead and not building with openssl 1.1.

- `wvdial` package and module were removed. This is due to the project being dead and not building with openssl 1.1.

- `cc-wrapper`'s setup-hook now exports a number of environment variables corresponding to binutils binaries, (e.g. `LD`, `STRIP`, `RANLIB`, etc). This is done to prevent packages' build systems guessing, which is harder to predict, especially when cross-compiling. However, some packages have broken due to this---their build systems either not supporting, or claiming to support without adequate testing, taking such environment variables as parameters.

- `services.firefox.syncserver` now runs by default as a non-root user. To accommodate this change, the default sqlite database location has also been changed. Migration should work automatically. Refer to the description of the options for more details.

- The `compiz` window manager and package was removed. The system support had been broken for several years.

- Touchpad support should now be enabled through `libinput` as `synaptics` is now deprecated. See the option `services.xserver.libinput.enable`.