Changelog

The canonical changelog lives in the firmware repo at CHANGELOG.md and is the source of truth — every release adds entries there. This page is a curated tour of the themes.

Unreleased

• Octopus tariff auto-detect — paste your API key + account number on Data sources, click Look up, and HeatSync proposes off-peak windows + peak/off-peak rates from your actual tariff. Supports Go, Cosy, Flux, Intelligent.
• DHW Combo mode — heats the cylinder during the warmest off-peak hour (cheapest electricity × highest COP at the same time).
• Settings IA refactor — Integrations renamed to Home Assistant (focused on outbound MQTT/HA); new Data sources tab for the external feeds the device pulls from (Weather, Carbon, Octopus).

v0.8.x — May 2026 — Smart hot water, polish, IA

The 0.8 series is dominated by hot-water intelligence and a substantial UI reorganisation.

• DHW Efficiency mode (v0.8.21) — picks the warmest hour from the weather forecast for the best heat-pump COP. Compound win with Combo mode (warmest off-peak).
• Cylinder learning (v0.8.21) — learns tank volume and reheat time from observed cycles; manual override available.
• Baseline-capture chip-temp calibration (v0.8.20) — fixes the on-die temp sensor that reads ~20 °C high on this die. ADR-002 has the why.
• WiFi scan + auto-roam + BSSID pin (v0.8.18) — fixes mesh installs latching onto a far AP at -91 dBm.
• HA entity audit + 7 derived sensors (v0.8.17) — mode-neutral names (“Flow temp” not “Heating flow”), and live_cop, dt_water, capacity_used, cylinder_volume, cylinder_loss, dhw_last_duration, building_ua.
• Settings hub IA (v0.8.0) — landing page at /config with tiles for Device / Energy / Home Assistant / Data sources / Sensors, Maintenance section for Firmware + Device info, Engineer tools for diagnostics + sniffer + API reference + FSV reference.
• HEATSYNC_BLE_ENABLED default → 0 (v0.8.17) — NimBLE arena was fragmenting heap below the 40 KB mbedTLS needs for TLS handshakes. BLE comes back on the AtomS3 migration (ADR-001).

v0.7.x — May 2026 — Carbon intensity & in-app updates

• Carbon-intensity tracker (v0.7.0) — pulls the National Grid’s regional gCO₂/kWh forecast every 30 min; powers Carbon-mode DHW scheduling.
• In-app updates (v0.6.0–v0.7.2) — Settings → Firmware shows current version, latest release, and an Install button. Manifest fetched from GitHub Pages; binary mirrored there too.
• Install overlay (v0.7.2) — full-screen progress + countdown during OTA install, with rollback hardening if the new image fails to boot.

v0.6.x — May 2026 — Heat-loss + Quiet mode

• Heat-loss + thermal-mass analyser (v0.6.0) — learns the building’s UA value (W/K) from observed cool-down events.
• Quiet mode write (v0.6.0) — sends the silence-mode enum to the unit.
• Calorimetric COP (v0.6.0) — Q ≈ flow × ΔT × Cp derived on every loop; shown live on the dashboard.

v0.5.x — April 2026 — MQTT and weather

• MQTT one-device discovery (v0.5.0) — every entity under one HeatSync device card in HA, rather than three (was indoor / outdoor / aux).
• Open-Meteo forecast (v0.5.0) — 48-hour forecast on the home page; the basis for what becomes Efficiency-mode scheduling.

v0.1.0 — May 2026 — Initial public release

• F1/F2 bus read path, dashboard, DHW schedule, MQTT auto-discovery, sniffer, FSV reference, OTA, BLE (compile-time gated).
• Hardware: M5 Atom Lite + Atomic RS485 Base, ~£25 BOM.

Pre-history

Before the docs site went up, development happened against a single Samsung EHS Mono install. Tagged releases start at v0.1.0; commit history runs further back.

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For per-release detail (every Added / Changed / Fixed / Removed entry, plus release procedure notes), see the full CHANGELOG.md on GitHub.