Meshtastic 2.7.21 Alpha: HTTP Deprecation and LNA Default

We’ve been behind on Meshtastic alpha coverage. Four new alphas have shipped since our 2.7.18 post in January. This post catches up on all of them, with 2.7.21 as the headliner because it’s the one with actual breaking warnings and behavior changes worth reading before you flash.

We haven’t rolled these across our network yet. Notes below come from the official Meshtastic release changelogs. If you’re running any of these alphas in the field, we’d love to hear what’s held up.

2.7.21 Alpha: The One to Read

Released 2026-04-06. This release has one deprecation warning you need to see and two behavior changes worth flagging.

Deprecation: HTTP server on original ESP32

The official release notes are direct about it: due to resource constraints, the HTTP server is deprecated on original-generation ESP32 devices and shouldn’t be relied on going forward. Support continues on ESP32-S3 and other newer ESP32 generations.

If you have nodes running on the original ESP32 (pre S3, pre C3), the web UI is going away. Plan accordingly. The recommended path forward is either migrating those nodes to ESP32-S3 hardware like the Heltec V3, or relying on the phone app and Bluetooth configuration instead of the HTTP server for those older boards.

Behavior change: LNA on by default for Heltec V4.3

2.7.21 enables the Low Noise Amplifier by default on the Heltec V4.3. Better receive sensitivity out of the box, at the cost of a small amount of idle current.

If this sounds familiar, it’s because MeshCore v1.15 made the same choice in the same month. Both firmwares decided that receive sensitivity should be on by default and let operators opt out for power-constrained deployments. For solar repeaters where every milliamp matters, verify the LNA setting after flashing and disable if your previous config had it off.

RAK 13302 power curve added

The RAK 13302 1W LoRa module now has a proper power curve in Meshtastic. If you’re running a RAK WisMesh 1W Booster kit, the firmware will report and manage transmit power more accurately across the 30 dBm range. A small change that matters if you’re doing link-budget math.

New hardware support

T5-4.7-S3 Epaper Pro added as a supported board
Heltec V4 TFT expansion kit gets proper MUI rotation handling
Heltec V4 WiFi map tile downloads adapted to the board’s constraints

Regulatory

Thailand NBTC 920-925 MHz limits applied. 27 dBm max TX power and 10% duty cycle enforced for Thailand-region devices.

UDP multicast integrity

Spoof detection added to UdpMulticastHandler, and PKI encryption (both pki_encrypted and public_key fields) now preserved when relaying UDP multicast packets to radio. For anyone running cross-LAN mesh bridges over UDP multicast, this is a correctness fix.

Build change worth mentioning

nRF52840 builds now use C++17. No user-visible impact, but it unlocks language features the project has been waiting on and may slightly reduce binary size.

Bug fixes worth noting

W5100S socket exhaustion was blocking MQTT and additional TCP clients on RAK4631 Ethernet gateways. Fixed. The related bug around Ethernet gateway API connection loss after W5100S brownouts is also fixed.
MQTT settings now persist even when the broker is unreachable at save time.
Traceroute hop rendering for ffff or unknown-dB hops. Better display instead of empty cells.
RAK WisMesh Tag low-voltage reboot hangs after app configuration. Fixed.
T-Echo touch-to-backlight now works on the base T-Echo, not just the Plus.
BMP detection during BME address scans. Previously the firmware could return early and miss a connected BMP sensor.
GPS baudrate locking removed from the Seeed Xiao S3 kit. Allows the GPS module to negotiate baud properly on boot.
NodeInfo suppression now only applies to external requests, not internal ones.

Catching Up: 2.7.20 and 2.7.19

2.7.20 alpha (2026-03-11)

Feature-heavy release with a few standouts.

Cardputer Kit added as a supported board
T-Beam 1W battery curve added for more accurate battery reporting on the 1W T-Beam
InkHUD Favorite Map Applet for e-ink devices with InkHUD
Transmit history persistence across reboots so traffic intervals are respected even after a restart
Late packet removal from TX queue when the queue fills. Prevents stale packets from backing up the radio
BaseUI Favorite Screen signal quality improvements
Large internal refactor switching delete to std::unique_ptr across several subsystems. No user-visible change, but reduces the surface area for memory bugs.

2.7.19 alpha (2026-02-11)

The other feature-heavy release in the gap. Headline items:

Significant NRF52 BLE power cuts and broader nRF52 power management improvements. If you run RAK4631, T-Echo, or other nRF52-based nodes on battery, this release measurably reduces idle draw.
AGC reset attempt added to help recover receive sensitivity in high-interference environments. Similar idea to MeshCore’s AGC reset interval.
BLE TX power configurable for nRF52 variants. Lets you trim BLE power for deployments where phone proximity is close and you want to save battery.
LR11x0 and SX128x long interleaving mode enabled. Improves resilience on noisy links.
Reply bot module with DM-only responses and rate limiting. Useful for automated responders without flooding public channels.
CW2015 LiPo fuel gauge support. Accurate battery readings on boards that have the chip.
Graduated NodeInfo send timeout based on active mesh size. Larger meshes get longer intervals, reducing chatter as node count grows.
InkHUD got bubbles, an on-screen keyboard, and menu improvements.
MeshSolar watchdog module for solar-powered deployments.
Hackaday Communicator function keys support.
Fully direct request and response support for more efficient point-to-point exchanges.

2.7.22 Alpha: Bug Fix Cleanup

Released 2026-04-14. Pure bug fixes and dependency updates, no new features.

TBeam heap blowout fix. The important one. If your TBeam has been mysteriously rebooting, this release likely resolves it.
Native build BinarySemaphorePosix implementation using proper pthread synchronization
Linux Input enable logic fix
PPA SFTP upload fix and Debian source cache extension
PlatformIO dependencies switched from PIO Registry to tagged GitHub zips (supply chain hygiene)
Various cppcheck cleanup and a const qualifier fix in the display path

If you’re on 2.7.21 and your TBeam has been unstable, 2.7.22 is the patch to take.

Should You Update

Depends on your hardware and risk tolerance.

If you’re on an original-generation ESP32 and rely on the HTTP server, read the 2.7.21 deprecation warning carefully before flashing. The HTTP server still works for now, but you shouldn’t build new workflows around it on that hardware.

If you’re running Heltec V4.3 or RAK WisMesh 1W nodes, 2.7.21 is worth it for the LNA default change and the RAK 13302 power curve respectively. Check your LNA setting after flashing if you’ve been running with it off for power savings.

If you’re on battery-powered nRF52 hardware, 2.7.19 is the alpha where BLE power got cut. Anyone running RAK4631 or T-Echo repeaters on battery should be on at least 2.7.19.

If your TBeams have been crashing, jump to 2.7.22 for the heap blowout fix.

If your nodes are stable and you don’t need any of the above, alphas are alphas. Wait for 2.7.x to hit beta or stable. That’s what the rest of the Meshtastic community does, and it’s the right call for mission-critical nodes.

How to Flash

Meshtastic firmware flashing is handled through the Meshtastic Web Flasher or via esptool and adafruit-nrfutil. For full walkthroughs, see our Meshtastic firmware guide.

For the full raw changelogs, pull them from the Meshtastic firmware releases page.

Comparing Meshtastic to MeshCore

If you’re weighing whether to stay on Meshtastic, add MeshCore alongside, or switch entirely, MeshCore 1.15 also dropped this month with its own set of changes. Both ecosystems are moving fast.