ExpressLRS 4.0 is lastly right here. This can be a main replace with significant enhancements in efficiency, flexibility, and reliability—but it surely additionally introduces vital compatibility modifications it’s essential perceive earlier than upgrading. In case your present setup is working completely, chances are you’ll not have to improve. But when a number of the new options and enhancements are interesting to you, be certain that to backup your config earlier than continuing.
Not Suitable with Older Variations
For those who set up ExpressLRS 4.0, it’ll NOT work with:
- Units nonetheless operating ELRS 3.x, 2.x, or 1.x
- Older STM32-based {hardware}, together with:
You need to replace each your transmitter (TX) and receiver (RX) to V4 for them to attach. They won’t talk in any other case.
Doesn’t Work with SPI Receivers (But?)
Some AIO flight controllers utilized in whoops have built-in SPI receivers. These are nonetheless operating ELRS 3.x code and won’t work with V4 but.
Since SPI ELRS firmware is built-in into Betaflight, assist relies on a Betaflight replace first.
There is no such thing as a point out within the 4.0 launch notice that SPI receivers are being deserted, so I presume it’s solely short-term. If you’re utilizing SPI receivers, don’t replace to ExpressLRS 4.0 but.
What’s New in ExpressLRS 4.0
Get the complete launch notice right here: https://github.com/ExpressLRS/ExpressLRS/releases. Right here’s a abstract.
Select Your Personal Arming Swap
Beforehand, Channel 5 had for use for the arm swap.
Now:
- With the choice arming technique, you possibly can assign a selected swap for arming.
- Channel 5 turns into a standard usable channel once more.
- Setup is extra versatile and handy.
- Requires EdgeTX 2.11.0 or larger
Higher Dynamic Energy
ExpressLRS now makes use of a better algorithm for dynamic energy.
This implies:
- Energy adjusts extra intelligently.
- Your sign stays sturdy with out always blasting most output.
- Higher battery life in your radio.
- Extra secure Hyperlink High quality (LQ) when utilizing dynamic energy.
Computerized Antenna Mode
Earlier than, you needed to manually choose antenna modes (Gemini, Ant1, Ant2, Swap).
Now, the transmitter and receiver determine it out robotically. No extra guessing or guide changes—it simply works.
What’s Gemini Mode? https://oscarliang.com/expresslrs-gemini/
Full Energy DJI Air Unit With no Flight Controller
This can be a massive one for fastened wing customers who don’t use a flight controller.
It’s identified that DJI air models don’t use full energy when it doesn’t detect an arm sign (despite the fact that when energy is ready to max). ExpressLRS receivers can now ship an arm sign on to DJI Air Items to set off full transmission energy—no flight controller required.
Quicker Telemetry
Telemetry is the info your drone sends again (battery voltage, GPS, sign power and so forth).
V4 enhancements:
- Telemetry velocity is quicker.
- Knowledge switch is extra dependable.
- “Sensor Misplaced” warnings are lowered.
When utilizing Gemini mode, telemetry bandwidth is sort of doubled.
New Net Interface (WebUI)
The configuration webpage has been redesigned:
- Cleaner format
- Simpler to make use of
- Higher organized
Performance stays comparable—simply extra polished and user-friendly.
Expanded Servo & Output Choices (Superior Customers)
For pilots utilizing PWM receivers or particular setups:
- Wider servo output vary (500–2500µs)
- Expanded failsafe vary
- DSHOT 3D assist
- Extra packet modes (particularly for LR1121 {hardware})
For those who don’t know what these are — you in all probability don’t want them
Lua Script Change
You also needs to replace the ExpressLRS LUA script in your radio.
The lua script is now referred to as: elrs.lua
Delete older variations comparable to:
This prevents duplicate ExpressLRS instruments from showing in your radio.
Necessary: Settings Could Be Wiped When Upgrading
Upgrading to V4 modifications the interior filesystem. Consequently, modified settings in WebUI could also be erased.
You need to again up your configuration earlier than updating. To do that, obtain the {hardware}.json file from the webUI earlier than updating after which changed after updating.
Closing Ideas: Ought to You Replace?
ExpressLRS 4.0 is a serious replace with important enhancements and new options. Nevertheless, it additionally breaks compatibility with older firmware variations and sure {hardware} (comparable to STM32-based units, and SPI receivers for now).
Earlier than upgrading:
- Make certain your {hardware} is supported.
- Again up your present configuration.
- Replace each TX and RX collectively.
In case your present setup works completely and not one of the new options are important to you, there’s no pressing have to improve. Hold flying and keep away from problem. For those who resolve to replace, do it rigorously—and ensure all the pieces is suitable first.