This issue is intended to track breaking changes for 8.0 which need a deprecation check implemented in the Deprecation Info API as they are made. While we will still need a review prior to the release of 8.0, the intention is that we can work on implementing these checks as the breaking changes are made, or at least keep a running list of which ones need checks rather than having to go through all >breaking PRs.

In order to be checkable by the Deprecation Info API, the issue must be detectable by examining one of the following:

1. ClusterState
2. IndexMetaData
3. Node-local information (e.g. settings, plugins, etc.)
4. DatafeedConfig

REST API changes, or problems which are only detectable by examining the contents of the index, rather than the mapping/settings, probably don't go here, but please ask if you're unsure.

Deprecation checks should generally be added to the 7.x branch. You can find the appropriate classes here. View the 6.8 branch for a number of examples if you need more examples than are present in 7.x.

The List

• Remove support for chained multi-fields Deprecate support for chained multi-fields. #41926 (check in Remove support for chained multi-fields. #42333) (This might be getting changed due to BWC concerns
• Bump the minimum Java version to Java 11 Bump the minimum Java version to Java 11 #40754 (check in Add deprecation check for Java version #41092)
• Add lower bound on ILM poll_interval Add lower bound on poll_interval #39593
• Remove include_relocations setting Remove include_relocations setting #47717
• Remove deprecated AUTH_PASSWORD setting Remove deprecated AUTH_PASSWORD setting #54892
• Remove slowlog level Remove slowlog level #57591
• Remove escape hatch permitting incompatible builds Remove escape hatch permitting incompatible builds #65753
• disallow creating geo_shape mappings with deprecated parameters disallow creating geo_shape mappings with deprecated parameters #70850
• Remove _tier allocation filtering settings Remove deprecated ._tier allocation filtering settings #73074
• Revert per-context painless cache & compilation limit Provide better compilation and cache stats to remove compiation rate limits #62899
• Security enabled by default for all license types Set xpack.security.enabled to true for all licenses #72300
• Remove special handling of disk watermark for single data node Breaking change for single data node setting #73737 (PRs need to be merged)
• Remove the pidfile setting Remove the pidfile setting #45940
• Scripting: Remove general cache settings Scripting: Remove general cache settings #59262
• Remove legacy role settings
• Disallow _field_names enabled setting Disallow _field_names enabled setting #46681
• Make remote cluster resolution stricter Make remote cluster resolution stricter #40419
• Remove deprecated search.remote settings Remove deprecated search.remote settings #42381
• Remove obsolete security settings Remove obsolete security settings #40496
• Remove node.max_local_storage_nodes Remove node.max_local_storage_nodes #42428
• Remove fixed_auto_queue_size threadpool type Remove fixed_auto_queue_size threadpool type #52280
• Remove join timeout Remove join timeout #60873
• Remove the client transport profile filter Remove the client transport profile filter #43236
• Remove support for delaying state recovery pending master Remove support for delaying state recovery pending master #53845
• Remove support for fractional byte size values Remove support for fractional byte size values #53927
• Remove frozen cache setting leniency Remove frozen cache setting leniency #71013
• Reject misconfigured/ambiguous SSL server config Reject misconfigured/ambiguous SSL server config #45892
• Remove support for sparse vectors Remove support for sparse vectors. #48781
• Do not set a NameID format in Policy by default Do not set a NameID format in Policy by default #44090
• Setting: cluster.routing.allocation.shard_state.reroute.priority Defer reroute when starting shards #44433
• Settings: discovery.zen.* Deprecate unused Zen1 settings #38289
• Setting: gateway.auto_import_dangling_indices New setting to prevent automatically importing dangling indices #49174
• Setting: http.content_type.required Enforce Content-Type requirement on the rest layer and remove deprecated methods #23146
• Setting: index.force_memory_term_dictionary Use reader attributes to control term dict memory useage #42838
• Setting: index.mapper.dynamic Remove MapperService#dynamic. #26603
• Settings: node.data, node.data_cold, node.data_content, node.data_frozen, node.data_hot, node.data_warm, node.ingest, node.master, node.ml, node.remote_cluster_client, node.transform, node.voting_only Introduce node.roles setting #58512
• Setting: repositories.fs.compress Blob store compression fix #39073
• Settings: http.tcp_no_delay, network.tcp.connect_timeout, transport.tcp.connect_timeout, transport.tcp.port, transport.tcp_no_delay Deprecate old transport settings #41229
• Setting: transport.tcp.compress Add additional transport compression options #74719
• Setting: xpack.data_frame.enabled [Transform]rename classes in transform plugin #46784
• Setting: xpack.watcher.history.cleaner_service.enabled Deprecate xpack.watcher.history.cleaner_service.enabled #37782
• Setting: indices.lifecycle.step.master_timeout Make ILM Steps use Infinite Master Timeout #74143
• Setting: xpack.eql.enabled Deprecate xpack.eql.enabled setting and make it a no-op #61375

Not needed list

• Provide an Option to Use Path-Style-Access with S3 Repo Provide an Option to Use Path-Style-Access with S3 Repo #41966
• Blob Store compress default to true Blob Store compress default to true #40033 (is this worth warning about? not sure what this breaks)
• Prevent PrefixTree strategies on new geo_shape indexes [GEO] Prevent PrefixTree strategies on new geo_shape indexes #37152 (for index templates)
• Remove the 'template' field in index templates Remove the 'template' field in index templates. #49460
• Remove type metadata from ingest documents Remove type metadata from ingest documents #50131
• Remove support for JAVA_HOME Remove support for JAVA_HOME #69149
• Parse empty first line in msearch request body as action metadata Parse empty first line in msearch request body as action metadata #41011
• Remove deprecated endpoints containing _xpack. Remove deprecated endpoints containing _xpack. #48170
• Remove the object format for indices_boost Remove the object format for indices_boost. #55078
• Remove use_field_mapping format option for docvalue fields Remove use_field_mapping format option for docvalue fields. #55622
• Removes typed URLs Removes typed URLs #41636
• Removes tpyed endpoints for msearch and mtermvector APIs Removes tpyed endpoints for msearch and mtermvector APIs #41674
• Removes typed URLs from mapping APIs Removes typed URLs from mapping APIs #41676
• Removes types from bulk API Removes types from bulk API #42194
• Removes type from TermVectors APIs Removes type from TermVectors APIs #42198
• Remove types from Get/MultiGet Remove types from Get/MultiGet #46587
• Remove per-type indexing stats Remove per-type indexing stats #47203
• Remove type query Remove type query #47207
• Remove include_type_name parameter from REST layer Remove include_type_name parameter from REST layer #48632
• Remove support for _type in searches Remove support for _type in searches #68564
• Remove support for string in unmapped_type Remove support for string in unmapped_type. #45675
• Add declarative parameters to FieldMappers Add declarative parameters to FieldMappers #58663
• Don't expose TextFieldMapper subfields Don't expose TextFieldMapper subfields #64597
• Allow parsing Content-Type and Accept headers with version Allow parsing Content-Type and Accept headers with version #61427
• Highlighters skip ignored keyword values Highlighters skip ignored keyword values #53408
• Percentiles aggregation: disallow specifying same percentile values twice Percentiles aggregation: disallow specifying same percentile values twice #52257
• Fix updating include_in_parent/include_in_root of nested field Fix updating include_in_parent/include_in_root of nested field. #54386
• Disallow changing 'enabled' on the root mapper Disallow changing 'enabled' on the root mapper. #54463
• Remove TypeFieldMapper Remove TypeFieldMapper #53611
• Scripting: Move script_cache into _nodes/stats Scripting: Move script_cache into _nodes/stats #59265
• Remove the no-jdk distribution Remove no-jdk distributions for 8.0 release #65109
• Fix range query on date fields for number inputs Fix range query on date fields for number inputs #63692
• Kibana user renamed to kibana_system Deprecate the kibana reserved user; introduce kibana_system user #54967
• kibana_user role renamed to kibana_admin Deprecating kibana_user and kibana_dashboard_only_user roles #46456
• Add validation for dynamic templates Add validation for dynamic templates #51233
• Remove support for chained multi-fields. Remove support for chained multi-fields. #42333
• Enforce Completion Context Limit Enforce Completion Context Limit #38675