Direct access to the sensor .raw_state member is now deprecated. Use get_raw_state() instead. The .raw_state member will be removed in ESPHome 2026.10.0.
This is a breaking change for external components in ESPHome 2026.4.0 and later.
The TEMPLATABLE_VALUE macro now uses TemplatableFn (4 bytes) instead of TemplatableValue (8 bytes) for trivially copyable types like float, uint32_t, bool, and enums. External components that call macro-generated setters with raw C++ constants instead of going through cg.templatable() will fail to compile.
This is a breaking change for external components in ESPHome 2026.4.0 and later.
Common entity trigger classes have been replaced with lightweight forwarder structs that fit inline in the callback system. The new build_callback_automation() API eliminates per-trigger object allocations. Several entity callback signatures have also changed to pass state as an argument.
This is a breaking change for external components in ESPHome 2026.4.0 and later.
The FlushResult enum introduced in ESPHome 2026.3.0 has been renamed to UARTFlushResult with prefixed enum values to follow ESPHome's naming conventions and avoid macro collisions.
This is a breaking change for external components in ESPHome 2026.4.0 and later.
wake_loop_threadsafe() and related wake primitives have moved from the socket component into core. The require_wake_loop_threadsafe() opt-in is deprecated (now a no-op) — wake works unconditionally on all platforms.
This is a breaking change for external components in ESPHome 2026.4.0 and later.
App.get_name() and App.get_friendly_name() now return const StringRef & instead of const std::string &. Most code compiles unchanged because StringRef provides .c_str(), .size(), .empty(), and implicit conversion to std::string. However, binding the result to const std::string & silently creates a heap-allocated temporary — update these references to const auto & to avoid the allocation.
This is a breaking change for external components in ESPHome 2026.3.0 and later.
The get_loop_priority() virtual method on Component is now only available when USE_LOOP_PRIORITY is defined. This define is only set on RP2040, the only platform where loop priority has an effect. External components that override get_loop_priority() must guard the override with #ifdef USE_LOOP_PRIORITY.
This is a breaking change for external components in ESPHome 2026.3.0 and later.
Component::call_loop(), Component::mark_failed(), and Component::call_dump_config() are no longer virtual methods. External components that override any of these methods must remove them entirely and move logic to loop() or dump_config(). This saves 800+ bytes of flash globally from vtable elimination.
This is a breaking change for external components in ESPHome 2026.3.0 and later.
The get_icon_ref(), get_icon(), get_device_class_ref(), and get_device_class() methods are deprecated on all platforms and replaced by new buffer-based APIs get_icon_to() and get_device_class_to(). On ESP8266, the old methods produce a static_assert error because the underlying strings have been moved to PROGMEM and cannot be accessed through normal C string pointers. On other platforms, the old methods continue to work but emit deprecation warnings and will be removed in 2026.9.0.
This is a breaking change for external components in ESPHome 2026.3.0 and later.
The http_request component's C++ API has been updated to use std::vector instead of std::map, std::list, and std::set for header handling. The get_response_headers() method (returning the full headers map) has been removed — use get_response_header(name) instead. Deprecated overloads using the old container types are provided until 2027.1.0.
This is a breaking change for external components in ESPHome 2026.3.0 and later.