MeshCore Firmware v1.17: New Radio Logic and JSON Config

MeshCore v1.17.0 shipped on August 9, 2026, across all three firmware variants (Room Server, Repeater, Companion). The biggest change is under the hood: a rewritten listen-before-talk scheme aimed at cleaner collision avoidance, plus a config format migration to JSON that every operator should know about before flashing. A long list of new hardware targets and bug fixes rounds out the release.

We haven’t rolled v1.17.0 across our production mesh yet. Notes below come from the official release announcement and the linked pull requests, cross-checked against GitHub directly for merge status and authorship.

Behavior Changes to Watch

Listen-before-talk rewrite. Probably the most consequential change in the release. The collision-avoidance logic got a significant rework, including fixes for cases where the radio’s IRQ flags get stuck and improved preamble detection. Per the release notes, the new scheme performs on par with hardware CAD but without the multi-second lock-up glitches CAD can suffer from. Hardware CAD stays off by default as a result.

Config now stored in JSON. All three firmware variants migrate their config to JSON format automatically on upgrade to 1.17.0. The old binary config is left intact, so you have a rollback path if you need to go back to older firmware.

New companion UI color scheme. Color displays get a visual refresh and should feel more responsive.

nRF52 hardware crypto. nRF52 targets now use CC310 hardware crypto functions instead of software crypto.

Faster ST7735 display driver. Benefits the Heltec T096 and Wireless Tracker, among other boards with that display.

Hibernate/poweroff power savings. Additional draw reduction during hibernate and poweroff states.

New Hardware Support

A busy release for new targets:

• Elecrow Thinknode M7 (plus groundwork for universal multi-interface companions, more below)
• Elecrow Thinknode M9
• Heltec RC32
• Heltec V4 R8
• Heltec Tower V2
• Nibble Zero Connect
• RAK ethernet modules
• Meshnology W12 (via a new generic LR2021 radio wrapper)
• Seeed SenseCAP MeshTracker X1

The X1 entry is a bit of personal news for us. That’s the port we built and upstreamed ourselves, landing across three PRs: #3112 for the base nRF52840/LR2021/GPS support, #3122 adding RGB status and haptic feedback, and #3139 from core team member oltaco adding QSPI flash support on top of what we shipped. If you’ve been running our community v2.0.0 build on an X1, official 1.17.0 now covers the same feature set, no separate firmware required going forward.

New Features

• MCU temperature in companion telemetry. One more data point in your sensor readout.
• room.post CLI command. New room server command for server-originated posts.
• Repeater power-off on long button press. No more pulling the battery to shut one down.
• set cad on/off CLI. Direct control over hardware CAD (see above for why you probably want it left off).
• get pwrmgt.bootreason CLI on ESP targets. Useful for diagnosing unexpected reboots.
• get/set radio.fem.rxgain CLI on supported Heltec boards.
• Steps toward universal companion. PR #3049 lays groundwork for companions to support up to 4 simultaneous serial interfaces (BLE plus USB, for example). No official multi-interface builds yet, but the plumbing is there.

Bug Fixes

A long list this release. The ones most likely to matter to operators:

• start ota failures now report properly on nRF devices instead of failing silently
• BLE bonded reconnect and receive queue fixes on ESP32
• Heltec V4 hardware USB serial fix
• T-Beam Supreme OLED fixes
• GPS time sync stall fix on long-uptime nodes
• External watchdog timer added for Heltec Tower V2
• SX1262 LDO support fix
• Boosted RX gain fix on LR1110
• Bad path_len values now rejected in PAYLOAD_TYPE_PATH and ANON_REQ packets, closing a potential crash/parsing edge case

Should You Update

Yes. The listen-before-talk rewrite is the kind of fix that improves a mesh’s overall reliability without you having to touch a single setting, and it’s the real headline for most operators. The JSON config migration is low-risk since the old config sticks around, but back up your node’s settings before flashing anyway, same as always.

If you’re running an X1 on our community build, this is the release that gets you onto official firmware for the first time. If you’ve been holding off on the X1 until it had upstream support, that blocker is gone too.

How to Update

Flash through MeshCore Flasher, or pull binaries directly from GitHub:

• Room Server v1.17.0
• Repeater v1.17.0
• Companion v1.17.0

If you’re comparing MeshCore against Meshtastic or just getting started, our MeshCore vs Meshtastic comparison covers the decision.