Quick Answer
Updating ExpressLRS firmware keeps your radio link reliable and unlocks new features. Use the free ELRS Configurator app to flash both your TX module and receivers over USB or Wi-Fi. The whole process takes about five minutes per device. The current stable release is v4.1, which is not backwards-compatible with v3.x hardware.
For more background on the protocol itself, see our complete ELRS explainer. If you want telemetry working after your update, our ELRS telemetry guide covers the setup. For choosing the right receiver hardware, see our ELRS receiver selection guide.
ExpressLRS v3 vs v4: What Changed and Why It Matters
The jump from v3 to v4 is the biggest breaking change in ExpressLRS history. Version 4.0 launched in early 2026 and introduced a new binding protocol, alternative arming (assign any channel, not just Channel 5), automatic antenna mode selection, and improved dynamic power that stops blasting max output when it does not need to. Version 4.1 refined the dynamic power algorithm further and reduced the annoying "Telemetry Lost" callouts that panicked new pilots.
| Feature | ELRS v3.x | ELRS v4.x (current) |
|---|---|---|
| Backwards compatible | Yes, with v2.x | No — TX and RX must both be v4 |
| Arming | Channel 5 only | Any channel (requires EdgeTX 2.11+) |
| Antenna mode | Manual selection | Automatic (TX and RX negotiate) |
| Dynamic power | Statistical, cautious | Improved — lowers power more aggressively |
| SPI receiver support | Yes (Betaflight 4.4+) | Yes (Betaflight 2026.06+) |
| DJI Air Unit full power | Requires flight controller | Direct from ELRS RX, no FC needed |
| Lua script | elrsV3.lua |
elrs.lua (delete old scripts) |
| WebUI settings | Preserved on update | Wiped on v4 upgrade — back up first |
Critical: SPI Receivers and Betaflight Dependency
If you fly a tiny whoop with a built-in SPI ELRS receiver (common on BetaFPV, Meteor75, and similar AIO boards), you cannot update the receiver independently. The ELRS firmware for SPI receivers is embedded inside Betaflight itself. ExpressLRS 4.x SPI support requires Betaflight 2026.06 or later. If your Betaflight version only supports ELRS 3.x SPI, keep your TX module on v3 until you update Betaflight. Do not flash your TX to v4 and leave your whoop on v3 SPI — they will not bind.
What You Need Before Updating
Download the ELRS Configurator for your operating system (Windows, macOS, or Linux). You need a USB data cable for your TX module or radio, and either USB or Wi-Fi for your receiver. Use a proper data cable, not a charge-only one. This catches people out regularly.
Check your current version via the ELRS Lua script on your radio. If the major version differs between TX and RX (for example, TX is 3.5 and RX is 4.2), update the older one first. Because v4 broke compatibility with v3, moving from v3 to v4 means updating both devices at the same time.
Back up before upgrading to v4. The v4 installer reformats the internal filesystem. Download your hardware.json from the WebUI before flashing, then re-upload it afterwards. Skip this and you lose all your custom settings.
Browse our full range of radio receivers and radio controllers and receivers for compatible hardware.
Updating Your TX Module
Plug your TX module into your radio's module bay or connect via USB. Open ELRS Configurator and select your device category. The Configurator auto-detects the hardware.
Select the latest stable release from the dropdown, pick your regulatory domain (EU 868MHz or FCC 915MHz if using 900MHz gear, though most UK pilots run 2.4GHz), and click "Flash." The process takes about 30 seconds. Our go-to module in the shop is the BetaFPV ELRS Nano TX Module, which flashes cleanly every time.
For internal radio modules like those in the RadioMaster TX16S, use the radio's USB connection directly. The Configurator treats it the same way.
Updating Your Receiver
There are three methods:
Via Wi-Fi (Easiest)
Hold the bind button for 10 seconds. The receiver creates a Wi-Fi hotspot called "ExpressLRS RX." Connect your phone or laptop, open 10.0.0.1 in a browser, and upload the firmware. This works on any ESP-based receiver like the SkyGuy Nano ELRS Receiver or the GEPRC ELRS Nano Dual Diversity Receiver.
Via Betaflight Passthrough
Connect your flight controller via USB. In ELRS Configurator, select "Betaflight Passthrough." This is the method we use most in the workshop because the FC is usually easier to reach than the receiver.
Via UART (Direct Serial)
Solder a serial adapter to the receiver's TX/RX pads. Only needed if Wi-Fi mode and passthrough both fail. We have rescued bricked receivers this way.
Common Update Problems
Configurator will not detect the device: Try a different USB cable. About half the "my device is broken" support queries we get are resolved by switching to a known data cable.
Receiver will not enter Wi-Fi mode: Double-check that the receiver has power (LED should be on). Some AIO boards need the flight controller powered too. Try Betaflight passthrough instead.
Binding fails after update: Re-bind both devices. Press the bind button on the TX module, then power cycle the receiver. They should link within five seconds. For a full walkthrough, see our ELRS receiver binding guide.
Lua script shows wrong version: Update the Lua script on your radio SD card. Download the latest from the ExpressLRS GitHub — the file is now called elrs.lua. Delete any old elrsV3.lua or elrsV3.luac files first, or you will get duplicate ExpressLRS tools on your radio.
Settings wiped after v4 upgrade: This is expected behaviour. The v4 installer reformats the config partition. Re-upload your hardware.json backup from the WebUI.
FAQ
Q: What is the latest version of ExpressLRS?
A: The current stable release is v4.1. ExpressLRS 4.0 launched in early 2026, and 4.1 followed with refined dynamic power, fewer false "Telemetry Lost" callouts, and the ability to set bind phrases directly from the handset Lua script.
Q: Can I mix different ELRS versions on TX and RX?
A: Within the same major version (3.x with 3.x, or 4.x with 4.x), yes. Mixing major versions causes binding issues. V4 specifically broke compatibility with v3, so a v4 TX will not talk to a v3 RX. Always match the major version.
Q: Do I need to re-bind after updating?
A: Usually not within the same major version. Across major version changes (especially v3 to v4), re-binding is required. It takes five seconds, so we re-bind after every update as a habit.
Q: Will updating erase my receiver settings?
A: Wi-Fi updates preserve your settings within the same major version. Upgrading from v3 to v4 wipes the config filesystem — back up your hardware.json first. Passthrough and UART flashes reset to defaults. Note down your binding phrase before flashing.
Q: How do I update an SPI receiver on a whoop?
A: SPI receivers are flashed as part of Betaflight, not through the ELRS Configurator. ExpressLRS 4.x SPI support requires Betaflight 2026.06 or later. Update Betaflight on your flight controller, then select "ExpressLRS" as the SPI protocol in the Receiver tab.