Sourced from retrofit's changelog.

Version 2.5.0 (2018-11-18)

• New: Built-in support for Kotlin's Unit type. This behaves the same as Java's Void where the body
  content is ignored and immediately discarded.
• New: Built-in support for Java 8's Optional and CompletableFuture types. Previously the 'converter-java8'
  and 'adapter-java8' dependencies were needed and explicitly adding Java8OptionalConverterFactory and/or
  Java8CallAdapterFactory to your Retrofit.Builder in order to use these types. Support is now built-in and
  those types and their artifacts are marked as deprecated.
• New: Invocation class provides a reference to the invoked method and argument list as a tag on the
  underlying OkHttp Call. This can be accessed from an OkHttp interceptor for things like logging, analytics,
  or metrics aggregation.
• New: Kotlin extension for Retrofit which allows you call create passing the interface type only as
  a generic parameter (e.g., retrofit.create<MyService>()).
• New: Added Response.success overload which allows specifying a custom 2xx status code.
• New: Added Calls.failure overload which allows passing any Throwable subtype.
• New: Minimal R8 rules now ship inside the jar requiring no client configuration in the common case.
• Fix: Do not propagate fatal errors to the callback. They are sent to the thread's uncaught
  exception handler.
• Fix: Do not enqueue/execute an otherwise useless call when the RxJava type is disposed by onSubscribe.
• Fix: Call RxJavaPlugins assembly hook when creating an RxJava 2 type.
• Fix: Ensure both the Guava and Java 8 Optional converters delegate properly. This ensures that converters
  registered prior to the optional converter can be used for deserializing the body type.
• Fix: Prevent @Path values from participating in path-traversal. This ensures untrusted input passed as
  a path value cannot cause you to make a request to an un-intended relative URL.
• Fix: Simple XML converter (which is deprecated) no longer wraps subtypes of RuntimeException
  or IOException when it fails.
• Fix: Prevent JAXB converter from loading remote entities and DTDs.
• Fix: Correctly detect default methods in interfaces on Android (API 24+). These still do not work, but
  now a correct exception will be thrown when detected.
• Fix: Report more accurate exceptions when a @QueryName or @QueryMap precedes a @Url parameter.
• Update OkHttp dependency to 3.12.

Version 2.4.0 (2018-03-14)

• New: Retrofit.Builder exposes mutable lists of the added converter and call adapter factories.
• New: Call adapter added for Scala's Future.
• New: Converter for JAXB replaces the now-deprecated converter for Simple XML Framework.
• New: Add Java 9 automatic module names for each artifact corresponding to their root package.
• Fix: Do not swallow Errors from callbacks (usually OutOfMemoryError).
• Fix: Moshi and Gson converters now assert that the full response was consumed. This prevents
  hiding bugs in faulty adapters which might not have consumed the full JSON input which would
  then cause failures on the next request over that connection.
• Fix: Do not conflate OkHttp Call cancelation with RxJava unsubscription/disposal. Prior to
  this change, canceling of a Call would prevent a cancelation exception from propagating down
  the Rx stream.

• 40621bf [maven-release-plugin] prepare release parent-2.5.0
• 8bd6c99 Prepare next development version
• 5d6650a Merge pull request #2967 from square/jakew/robo/2018-11-18
• 23592bc Merge pull request #2968 from square/jakew/okhhtp/2018-11-18
• 01e024b Update OkHttp to 3.12
• 7d8dd16 Update Robolectric
• f0cad11 Merge pull request #2962 from square/jakew/completable-future-android/2018-11-16
• bc62069 Merge pull request #2963 from square/jakew/nullability/2018-11-16
• 7dcac1d Merge pull request #2964 from square/jakew/header-tests/2018-11-16
• 07cb4ae Add tests for form and multipart header values and overrides
• Additional commits viewable in compare view

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot ignore this [patch|minor|major] version will close this PR and stop Dependabot creating any more for this minor/major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
• @dependabot use these labels will set the current labels as the default for future PRs for this repo and language
• @dependabot use these reviewers will set the current reviewers as the default for future PRs for this repo and language
• @dependabot use these assignees will set the current assignees as the default for future PRs for this repo and language
• @dependabot use this milestone will set the current milestone as the default for future PRs for this repo and language

You can disable automated security fix PRs for this repo from the Security Alerts page.