This is a list to track all deprecated code or old usages that need to be removed on 3.0.

• [Version] Remove all Legacy 7.x Compatibility in 3.0 #2748
• [REMOVE] Cleanup deprecated thread pool settings #2595
• Remove copy_settings parameter from split and shrink AP
• Remove boost parameter on field mapping
• CamelCase nGram and edgeNGram token filters
• DateHistogram interval parameter
• Adjacency matrix setting max_adjacency_matrix_filters
• Sort orders on _time and _term
• Index template with multiple mappings
• boost parameter on field mapping
• local parameter on cat nodes api
• local parameter in get field mapping requests
• Some 'gateway' settings used to defer cluster recovery Remove deprecated 'gateway' settings used to defer cluster recovery pending a certain number of master nodes #3117
• package, (public and protected) class and method that contains "master" terminology and deprecated in version 2.x in issue Replace "master" terminology in Java APIs #1684
• package, (public and protected) class and method that contains "whitelist" terminology and deprecated in version 2.x in issue Replace "blacklist/whitelist" terminology in Java APIs #1683
• Codes that add the node name to the logging configuration [BUG] legacy code in LogConfigurator #4274
• [Remove] Deprecated serialization logic from pipeline aggs #4847
• COMPAT locale provider will be removed in a future release #11550