Tesla began pushing Full Self-Driving (Supervised) v14.3.8 on 26 August 2026, inside firmware 2026.26.6.5. It is a Hardware 4 build for North America, covering Model S, Model 3, Model X, Model Y and Cybertruck, and it started the day at 0% of the fleet with no cars tracked.

Read the FSD release notes and you will find nothing new. Read the version number in front of them and you will.

The merge is the news

Until this build, a North American HW4 owner had to choose which half of Tesla's software they wanted. The 2026.26 Summer Update brought Caraoke with scoring, expanded Grok commands, anytime Camera Preview, custom wraps and speed cameras on the route. The newest FSD sat somewhere else entirely — v14.3.7 shipped in 2026.21.5, five branches back.

The 2026.26 builds that followed did not close the gap. 2026.26.6.1 on 14 August and 2026.26.6.2 on 22 August were both logged as fixes, with no new FSD version attached to either. 2026.26.6.5 is the first to carry both: the Summer Update feature set and a current 14.3 release, in one install.

Europe reached the same junction two days earlier and from the other direction. 2026.27.100.1 merged the Summer Update into European FSD cars on 24 August, but at FSD v14.2.2.6 — the merged EU branch, not 14.3.

The FSD notes have not moved since v14.3.6

The FSD section of 2026.26.6.5 is the same text Tesla attached to v14.3.7, which was itself identical to v14.3.6. That is three consecutive builds under one changelog:

  • an upgraded reinforcement-learning stage in neural-network training
  • an upgraded vision encoder, for rare and low-visibility scenes, 3D geometry and traffic signs
  • an AI compiler and runtime rewritten with MLIR, for a claimed 20% faster reaction time
  • reduced lane biasing and minor tailgating
  • more decisive parking-spot selection, with the predicted pin shown as a P on the map
  • better response to emergency vehicles, school buses and right-of-way violators
  • improved handling of small animals, and of objects leaning into the vehicle path
  • stricter driver monitoring, with better gaze tracking and eyewear handling
  • one unified model across Actually Smart Summon, FSD and Robotaxi

Several of these are older than they look. The MLIR rewrite and its 20% figure have been in the notes since v14.3.5 in July.

What repeated notes usually mean

When Tesla ships successive builds under matching text, the work is maintenance: neural-net tuning, regression fixes, no headline addition. v14.3.7 was exactly that — a build whose purpose was to undo v14.3.6's braking regressions. Treat v14.3.8's notes as a version stamp rather than a changelog and you will read the release correctly.

That leaves the base firmware as the substantive change, and for an owner it is the more useful one. It removes the trade-off.

Rollout

At release the build was on no cars at all. The 14.3 branch has not rolled out quickly in recent months — v14.3.7 was still under 1% of the HW4 fleet five days after launch — so a slow, wave-by-wave widening is the base case rather than a rapid push.

What European owners get

Nothing from this one. Europe stays on its own merged branch at FSD v14.2.2.6, and the 14.3 series has still not crossed the Atlantic. The useful read for a European HW4 owner is precedent rather than product: North America has now shown that the Summer Update and a current 14.3 build can ship together, which is the shape the European branch would have to take whenever 14.3 does arrive here.