- Added support for the `${VAR:?err}` and `${VAR?err}` variable interpolation
  syntax to indicate mandatory variables

#### Compose file version 2.x

- Added `priority` key to service network mappings, allowing the user to
  define in which order the specified service will connect to each network

#### All formats

- Added `--renew-anon-volumes` (shorthand `-V`) to the `up` command,
  preventing Compose from recovering volume data from previous containers for
  anonymous volumes

- Added limit for number of simultaneous parallel operations, which should
  prevent accidental resource exhaustion of the server. Default is 64 and
  can be configured using the `COMPOSE_PARALLEL_LIMIT` environment variable

- Added `--always-recreate-deps` flag to the `up` command to force recreating
  dependent services along with the dependency owner

- Added `COMPOSE_IGNORE_ORPHANS` environment variable to forgo orphan
  container detection and suppress warnings

- Added `COMPOSE_FORCE_WINDOWS_HOST` environment variable to force Compose
  to parse volume definitions as if the Docker host was a Windows system,
  even if Compose itself is currently running on UNIX

- Bash completion should now be able to better differentiate between running,
  stopped and paused services

### Bug fixes

- Fixed a bug that would cause the `build` command to report a connection
  error when the build context contained unreadable files or FIFO objects.
  These file types will now be handled appropriately

- Fixed various issues around interactive `run`/`exec` sessions.

- Fixed a bug where setting TLS options with environment and CLI flags
  simultaneously would result in part of the configuration being ignored

- Fixed a bug where the DOCKER_TLS_VERIFY environment variable was being
  ignored by Compose

- Fixed a bug where the `-d` and `--timeout` flags in `up` were erroneously
  marked as incompatible

- Fixed a bug where the recreation of a service would break if the image
  associated with the previous container had been removed

- Fixed a bug where updating a mount's target would break Compose when
  trying to recreate the associated service

- Fixed a bug where `tmpfs` volumes declared using the extended syntax in
  Compose files using version 3.2 would be erroneously created as anonymous
  volumes instead

- Fixed a bug where type conversion errors would print a stacktrace instead
  of exiting gracefully

- Fixed some errors related to unicode handling

- Dependent services no longer get recreated along with the dependency owner
  if their configuration hasn't changed

- Added better validation of `labels` fields in Compose files. Label values
  containing scalar types (number, boolean) now get automatically converted
  to strings

## 1.18.0

(2017-12-18)

### New features

#### Compose file version 3.5

- Introduced version 3.5 of the `docker-compose.yml` specification.
  This version requires Docker Engine 17.06.0 or above

- Added support for the `shm_size` parameter in build configurations

- Added support for the `isolation` parameter in service definitions

- Added support for custom names for network, secret and config definitions

#### Compose file version 2.3

- Added support for `extra_hosts` in build configuration

- Added support for the [long syntax](/reference/compose-file/legacy-versions.md) for volume entries, as previously introduced in the 3.2 format.
  Using this syntax will create [mounts](/manuals/engine/storage/bind-mounts.md) instead of volumes.

#### Compose file version 2.1 and up

- Added support for the `oom_kill_disable` parameter in service definitions
  (2.x only)

- Added support for custom names for network definitions (2.x only)


#### All formats

- Values interpolated from the environment will now be converted to the
  proper type when used in non-string fields.

- Added support for `--label` in `docker-compose run`

- Added support for `--timeout` in `docker-compose down`

- Added support for `--memory` in `docker-compose build`