ESPHome 2026.4.0 Brings a Big Performance Boost for the Espressif ESP32 — with Breaking Changes Too

The ESPHome project has officially launched the latest version of its popular home automation firmware for Espressif ESP-family and other microcontrollers — bringing with it boosted performance, thanks in no small part to a shift to running chips at their maximum supported frequency.

"ESPHome 2026.4.0 delivers major performance and reliability improvements across all platforms," the project's maintainers say of the new version. "[Espressif] ESP32 devices default to maximum CPU frequency (33% faster API operations), unlock 40kB extra IRAM [Instruction RAM], signed OTA [Over-The-Air update] verification, and custom partition tables. ESP8266 gets a crash handler matching ESP32/RP2040, and a new client-side state logging architecture achieves up to 46× faster sensor publishing by moving log formatting off the device. Bluetooth Proxy advertisement forwarding (the constant hot path) dropped to just ~1.8% of main loop time on ESP32-C3."

Originally founded, as the name implies, as a project to bring home automation capabilities to Espressif's ESP8266 and ESP32 microcontroller families, ESPHome — now under the auspice of the Open Home Foundation alongside Home Assistant — has since grown to support other devices including the Raspberry Pi RP2040, Nordic Semiconductor nRF52, Realtek RTL87xx, and Beken BK72xx microcontrollers, plus the ability to run selected components on desktop platforms. The promised performance gains in the latest version, though, will mostly be felt by those running the firmware on an Espressif ESP32-, ESP32-S2, ESP32-S3, or ESP32-C5 — thanks to a move to running at the highest officially-supported CPU frequency.

"[Espressif] ESP32, ESP32-S2, ESP32-S3, and ESP32-C5 now default to 240MHz instead of 160MHz," the ESPHome maintainers explain. "This restores the performance level that Arduino users had before May 2025 and delivers ~34% faster CPU-bound operations: API encryption handshake [goes from] 90ms to 64ms (29% faster); protobuf encoding (BLE proxy) [is] 34% faster; noise encryption [is] 33-34% faster across all payload sizes. Users on battery power or with thermal constraints can override with cpu_frequency: 160MHZ. This is a breaking change as it increases power consumption on affected variants."

The original ESP32 also benefits from an additional 40kB of instruction memory, reclaimd from previously-reserved SRAM1 blocks. "ESPHome will automatically detect your bootloader version at boot and suggest enabling this option only when it is safe to do so," the maintainers advise. "Do not enable this option without the bootloader check confirming it is safe; enabling it with a pre-v5.1 bootloader will brick the device (requiring USB reflash to recover)."

Other changes include the ability to require signed Over-The-Air (OTA) updates, custom partition table support, a fix for crashes in analog to digital conversion (ADC), another for a "long-standing brick hazard" in the web server, and a fix for crashes in mDNS. The ESP8266, meanwhile, gets a new crash handler, while all ESP devices benefit from preliminary support for ESP-IDF 6.0. The Raspberry Pi RP2040 gets new support for WIZnet Ethernet devices and Microchip's ENC28J60 10-BASE-T controller, there's new compatibility with general-purpose input/output (GPIO) expanders, memory optimizations across all platforms, and an upgrade to version 9 of the LVGL graphics library — a breaking change that will require some programs to be modified in order to run under the new firmware.

A full list of changes, including all the new sensors added in the latest release, is available on the ESPHome website; the project's source code is available on GitHub under the ESPHome license, which uses the permissive MIT license or the reciprocal GNU General Public License 3 depending on which part of the codebase you're looking at.