What changed for tuning in Betaflight 2025.12 and 2026.6

The biggest tuning change in Betaflight 2025.12 is the D-term rename. Up to 4.5, d_roll is the peak D and d_min_roll is the base D. From 2025.12, d_roll is the base D and the peak moved to d_max_roll. Paste a 4.5 diff into 2025.12 and the two values swap places. 2025.12 also changed two feedforward defaults. 2026.6 then decoupled D max gain from D max advance, fixed the gyro scale on one gyro chip and added an experimental Autotune tab.

The D-term rename in 2025.12

Betaflight has two D values per axis: a base D used when the sticks are still and the air is calm, and a peak D that it can rise to during fast moves and propwash. The names for them changed:

It is a change of meaning, not just of names. d_roll 40 from a 4.5 diff becomes a base D of 40 on 2025.12, higher than the old peak. The old d_min_roll line doesn’t exist any more, so the new peak stays at its default. When dynamic D was off on 4.5 (base and peak the same), the single D value sits in d_roll in both versions.

To move a tune across, convert it with the values, not a find-and-replace on names. The free setting-name converter does that for a whole diff.

Feedforward defaults in 2025.12

Two feedforward defaults changed, so a quad on default feedforward settings feels a little different after the upgrade:

Both make feedforward smoother on noisy radio links, at the cost of a little sharpness. 2025.12 also added yaw hold settings for feedforward, feedforward_yaw_hold_gain (default 15) and feedforward_yaw_hold_time (default 100).

Other 2025.12 changes that touch tuning

• More dynamic notches. dyn_notch_count can go up to 7, from 5. The default is still 3.
• Debug mode for logging. GYRO_SCALED no longer exists. Unfiltered gyro is logged as standard, so debug_mode can stay NONE for tuning logs. See blackbox logging for tuning.
• Motor idle. dshot_idle_value is now motor_idle.

What changed in 2026.6

• D max gain and D max advance were decoupled. In the 2026.6 firmware, d_max_gain defaults to 0 and d_max_advance to 35. Before, they were 37 and 20. A tune carried over keeps its own values. With the new defaults, D rises with stick movement (advance) and not with gyro error (gain). Check get d_max in the CLI on your build before comparing tunes.
• Gyro scale fix on IIM-42652 boards. This gyro was set to ±4000 °/s and is now ±2000 °/s, which effectively doubles the PID gains on those boards. Betaflight’s release notes say to reset and re-tune the PIDs after upgrading, and not to fly the old tune.
• New filter implementation. The firmware’s biquad filters were replaced with state variable filters, and the filter type that read BIQUAD now reads SVF. The intended filtering behaviour is the same.
• RPM filter in the app. Harmonic count, Q and minimum frequency can now be edited on the PID Filters page instead of only in the CLI. See how to set up RPM filtering.
• Thrust linearisation rescaled. The thrust_linear curve changed shape, so an existing value gives a slightly different curve after the upgrade.
• Absolute Control removed. The abs_control_* settings are gone.
• Experimental Autotune tab. It analyses a log from a chirp test (a frequency sweep Betaflight flies on a switch) and recommends simplified tuning slider values. It sits behind Expert Mode. See Betaflight Autotune compared.

Earlier changes still in many diffs

Plenty of quads still run 4.3 or 4.4, and diffs from them get passed around:

• Anti-gravity was rewritten in 4.4. On 4.3, anti_gravity_gain runs 0–30000 with a default of 3500. From 4.4 it runs 0–250 with a default of 80, and anti_gravity_cutoff_hz (5) and anti_gravity_p_gain (100) were added. A 4.3 value pasted into 4.4 or newer is far out of range.
• TPA moved in 4.4. On 4.3 the TPA settings live in the rate profile. From 4.4 they are in the PID profile, so they follow the PID profile you select.
• The dynamic notch minimum dropped in 4.4, from 150 Hz to 100 Hz.
• 4.5 added low-throttle TPA (tpa_low_rate 20, tpa_low_breakpoint 1050) and per-harmonic RPM filter weights (rpm_filter_weights, 100,100,100).

Before you paste an old diff into new firmware

1. Save a full diff all from the old firmware first.
2. Convert the D-term lines with their values, or use the setting-name converter.
3. Check anti-gravity if the diff comes from 4.3.
4. On an IIM-42652 board going to 2026.6, start from default PIDs instead.
5. After pasting, arm on the ground, hover for about 20 seconds, land and touch the motors before you fly hard.

How FPV PID Tune handles it

FPV PID Tune reads the firmware version when you plug in and uses that version’s setting names for every value it writes, including the D-term swap. It supports Betaflight 4.3 to 2026.6. If you update the firmware in the middle of a tune, it starts a new baseline on the new firmware and keeps the earlier rounds as background.