Tesla has started rolling out software version 2026.21.5, which delivers Full Self-Driving (Supervised) v14.3.7 to Model 3, Model Y, Model S, Model X, and Cybertruck vehicles running Hardware 3 or Hardware 4. According to release notes tracked by Not a Tesla App, the update began reaching cars on August 1, 2026, separate from the broader 2026 Summer Update that shipped the same month.
The headline change is under the hood. Tesla rewrote the AI compiler and runtime using MLIR, which the company says produces a 20% faster reaction time and speeds up how quickly new models can be trained and shipped. The update also upgrades the neural network’s vision encoder, which Tesla says improves understanding in rare and low-visibility scenarios and strengthens how the car reads traffic signs and 3D geometry.
On the road, the release focuses on traffic light handling at complex intersections — compound lights, curved approaches, and stopping cleanly for yellow lights — along with reduced lane-biasing and tailgating behavior and more decisive parking-spot selection. Tesla also says the car responds better to emergency vehicles, school buses, and small animals near the road, and recovers automatically from temporary system hiccups without requiring driver intervention.
A few other features round out the release. Actually Smart Summon is now available on Cybertruck, with its top speed raised to 8 mph. The in-car camera preview, which the July Summer Update added for use in Park, now also works while driving. And Tesla says it unified the underlying model across Smart Summon, FSD, and its Robotaxi service, aiming for more consistent behavior across all three.
As with prior FSD releases, 2026.21.5 is rolling out gradually rather than to the whole fleet at once. Fleet-tracking site Teslascope shows installs concentrated on newer Hardware 4 vehicles in North America roughly a week and a half into the rollout, with older Hardware 3 cars — which are also eligible per Tesla’s release notes — following on a slower timeline. Owners can check whether the update has reached their car under Software on the vehicle’s touchscreen; Tesla’s in-app release notes remain the official source for exactly what shipped to a given car.
Photo by Leonardo Gonzalez.