Version 2.1.6

• Add a new config option to specify the directories containing resource classes
• Fix a bug regarding the ordering filter when dealing with embedded fields
• Allow to autowire the router
• Fix the base path handling the Swagger/Open API documentation normalizer

Version 2.2.0 beta 1

• Add GraphQL support (including mutations, pagination, filters, access control rules and automatic SQL joins)
• Fully implement the GraphQL Relay Server specification
• Add JSONAPI support
• Add a new @ApiFilter annotation to directly configure filters from resource classes
• Add a partial paginator that prevents COUNT() SQL queries
• Add a new simplified way to configure operations
• Add an option to serialize Validator's payloads (e.g. error levels)
• Add support for generators in data providers
• Add a new allow_plain_identifiers option to allow using plain IDs as identifier instead of IRIs
• Add support for resource names without namespace
• Automatically enable FOSUser support if the bundle is installed
• Add an AbstractCollectionNormalizer to help supporting custom formats
• Deprecate NelmioApiDocBundle 2 support (upgrade to v3, it has native API Platform support)
• Deprecate the ApiPlatform\Core\Bridge\Doctrine\EventListener\WriteListener class in favor of the new ApiPlatform\Core\EventListener\WriteListener class.
• Remove the api_platform.doctrine.listener.view.write event listener service.
• Add a data persistence layer with a new ApiPlatform\Core\DataPersister\DataPersisterInterface interface.
• Add the a new configuration to disable the API entrypoint and the documentation
• Allow to set maximum items per page at operation/resource level
• Add a new alwaysIdentifier configuration option for properties that force serializer to generate an IRI for the relation

Version 2.1.5

• Add support for filters autoconfiguration with Symfony 3.4+
• Add service aliases required to use the autowiring with Symfony 3.4+
• Allow updating nested resource when issuing a POST HTTP request
• Add support for the immutable date and time types introduced in Doctrine
• Fix the Doctrine query generated to retrieve nested subresources
• Fix several bugs in the automatic eager loading support
• Fix a bug occurring when passing nor an IRI nor an array in an embedded relation
• Allow to request 0 items per page in collections
• Also copy the Host from the Symfony Router
• Paginator::getLastPage() now always returns a float
• Minor performance improvements
• Minor quality fixes

Version 2.1.4

• Symfony 3.4 and 4.0 compatibility
• Autowiring strict mode compatibility
• Fix a bug preventing to create resource classes in the global namespace
• Fix Doctrine type conversion in filter's WHERE clauses
• Fix filters when using eager loading and non-association composite identifier
• Fix Doctrine type resolution for identifiers (for custom DBALType)
• Add missing Symfony Routing options to operations configuration
• Add SubresourceOperations to metadata
• Fix disabling of cache pools with the dev environment

Version 2.1.3

• Don't use dynamic values in Varnish-related service keys (improves Symfony 3.3 compatibility)
• Hydra: Fix the value of owl:allValuesFrom in the API documentation
• Swagger: Include the context even when the type is null
• Minor code and PHPDoc cleanups

Version 2.1.2

• PHP 7.2 compatibility
• Symfony 4 compatibility
• Fix the Swagger UI documentation for specific routes (the API request wasn't executed automatically anymore)
• Add a missing cache tag on empty collections
• Fix a missing service when no Varnish URL is defined
• Fix the whitelist comparison in the property filer
• Fix some bugs regarding subresources in the Swagger and Hydra normalizers
• Make route requirements configurable
• Make possible to configure the Swagger context for properties
• Better exception messages when there is a content negotiation error
• Use the PriorityTaggedServiceTrait provided by Symfony instead of a custom implementation
• Test upstream libs deprecations
• Various quality fixes and tests cleanup

Version 2.1.1

• Fix path generators
• Fix some method signatures related to subresources
• Improve performance of the deserialization mechanism

Version 2.1.0

• Add a builtin HTTP cache invalidation system able to store all requests in Varnish (or any other proxy supporting cache tags) and purge it instantly when needed
• Add an authorization system configurable directly from the resource class
• Add support for subresources (like /posts/1/comments or /posts/1/comments/2
• Revamp the automatic documentation UI (upgraded to the React-based version of Swagger UI, added a custom stylesheet)
• Add a new filter to select explicitly which properties to serialize
• Add a new filter to choose which serialization group to apply
• Add a new filter to test if a property value exists or not
• Add support for OAuth 2 in the UI
• Add support for embedded fields
• Add support for customizable API resources folder's name
• Filters's ids now defaults to the Symfony's service name
• Add configuration option to define custom metadata loader paths
• Make Swagger UI compatible with a strict CSP environment
• Add nulls comparison to OrderFilter
• Add a flag to disable all request listeners
• Add a default order option in the configuration
• Allow to disable all operations using the XML configuration format and deprecate the previous format
• Allow upper cased property names
• Improve the overall performance by optimizing RequestAttributesExtractor
• Improve the performance of the filters subsystem by using a PSR-11 service locator and deprecate the FilterCollection class
• Add compatibility with Symfony Flex and Symfony 4
• Allow the Symfony Dependency Injection component to autoconfigure data providers and query extensions
• Allow to use service for dynamic validation groups
• Allow using PHP constants in YAML resources files
• Upgrade to the latest version of the Hydra spec
• Add pagination and itemPerPage parameters in the Swagger/Open API documentation
• Add support for API key authentication in Swagger UI
• Allow to specify a whitelist of serialization groups
• Allow to use the new immutable date and time types of Doctrine in filters

Version 2.0.11

• Ensure PHP 7.2 compatibility
• Fix some bug regarding Doctrine joins
• Let the hydra_context option take precedence over operation metadata
• Fix relations handling by the non-hypermedia ItemNormalizer (raw JSON, XML)
• Fix a bug in the JSON-LD context: should not be prefixed by #
• Fix a bug regarding serialization groups in Hydra docs

Version 2.1.0 beta 2

A lot of bug fixes and performance improvement.
Changelog: https://github.com/api-platform/core/blob/master/CHANGELOG.md#210

For the differences with 2.1.0 beta 1, check v2.1.0-beta.1...v2.1.0-beta.2.