In previous articles, I have covered how Ukrainian forces have utilised and adapted open-source applications and commercially available products (e g, FPV drones). However, developments on the Russian side of the war have not been covered to the same extent. This article will cover how Russian developers have adapted the software used to program and control FPV drones, and how those modifications have aided Russian units in countering Ukrainian electronic warfare (EW) efforts. To understand how we can use drones and counter them, we need to know how Russian units are adapting to the ever-changing battlespace.
An overwhelming majority of drones used in Ukraine by both sides rely on open-source software such as Betaflight and Express Long Range System (ELRS). Betaflight is used to configure the drone’s flight controller, which in turn controls all sensors and peripherals such as video transmitters, motors, and servos (used to trigger payloads). ELRS links the drone’s radio receiver to the operator’s ground control (I e, hand control). In their standard configuration, the user can choose which frequencies to use within a fixed range, in accordance with peacetime regulations. However, the source code is openly available, and anyone with programming knowledge can modify the software as they see fit, which we are seeing in the ongoing Russo-Ukrainian war.
One particular Russian group, which initially served as a donation collector for Russian units, began developing a modified ELRS version in 2024. In August, the modification was named TLRS (said to stand for Totalitarian LRS) with version number 5.2. Almost a year later, the tenth version was released. During that period, the software not only enabled Russian FPV pilots to choose from a wide range of frequencies[1] but also created a link protocol adapted to Ukrainian CUAS efforts. Especially the Ukrainian method that EW operators use to spoof the drone’s control signal and kill the motors mid-air, or turn the drone upside down, forcing it to crash.
The creators also claimed to have modified the existing Frequency-Hopping Spread Spectrum (FHSS) built into ELRS and replaced it with a new algorithm to make it harder to fake the flow of data packets. Other modifications aimed at keeping the drone airborne as long as possible, even without a stable control link with the operator. Usually, when the receiver doesn’t receive data from the transmitter, the drone will ”failsafe”[2] within seconds, meaning its motors will stop. The Russian modification extended the failsafe time and deactivated the ability to turn off the motors while airborne. Which, however, also meant that a legitimate operator could not turn off the motors once the drone had been armed, leading to some injuries. Although the group behind TLRS claims to have discontinued development of the software, it is likely still distributed to Russian drone units via the Telegram app. The authors still develop and distribute a version of Betaflight called TBF[3]. This software complements TLRS in the same way that ELRS complements Betaflight, and it also focuses on keeping the drone airborne when the connection with the pilot is lost. When writing this, the latest known version, at least to the public, is TBF 7.7, which was released December 16 2025. That version is said to warn the operator when the drone receives a disarm command, indicating that a qualified CUAS asset is in that area. To this writer’s knowledge, Russian actors have not yet been able to emulate the Ukrainians in directing the pilot to determine which direction the EW asset might be located.
However, what is more interesting to note is that the creators seem to have had continuous input from the field, as evidenced by monthly or even bi-weekly updates to the software and knowledge of which software version still worked best in which area. These inputs likely affected which features were released and how those functions were designed. Features like switching video frequency mid-air, ”suicide” functions for lost drones or activating or deactivating on-screen masking to hide the launch point’s location and thus the drone squad’s location.
All the above is just the work done by one group. As far as I can tell, there are at least 25 different builds, and around four have been regularly updated during 2025. Not counting the Ukrainian software builds. The number of software builds highlights both the demand from troops on the ground for access to adapted software and the role of real-world testing in determining which software survives and thrives.
Something to be on the lookout for this year is the use of another popular drone software, iNAV[4]. This software is popular because it enables pilots to plan drone missions for autopilot flight using various commercially available navigation sensors (such as optical rangefinders[5]). That particular software has already modified into a ”totalitarian” version. Also, with the latest official Betaflight release, features such as position and altitude hold were introduced to users. Of course, these functions are of interest to actors in the Russo-Ukrainian war, and Russian programmers have already begun exploring the possibility of drones maintaining altitude using GPS, magnetic compasses, and built-in barometers. Thus, radio-controlled FPV drones will likely continue to dominate the battlespace in 2026, enhanced with autonomous functionality. This functionality can, of course, also be added to drones with fibre-optic cables, meaning that even if someone cuts the cable, the drone will continue to fly in the direction of travel (at least). Creating a new set of dilemmas for the soldiers to handle and overcome. Thus, the deadly dance of action and counteraction continues.