MTPLX 2.7.1

Fixes

• xhigh stays selected. Picking it in Inference settings while the model was running snapped straight back to medium, and mtplx config set reasoning_effort xhigh was refused outright. Those two places each carried their own copy of the effort list and neither had been told about xhigh, even though the engine had understood it since 2.7.0. The live-settings save is all-or-nothing, so one unrecognized level threw away the entire save and the picker reverted. Every place that accepts an effort level now reads the same list, and which levels a given model offers is still decided by that model alone.
• KV cache quantization reaches Qwen 3.8. The toggle displayed q8 but the launch path only recognized Qwen 3.5 and 3.6, so a 3.8 run quietly got nothing.
• mtplx doctor names the model it actually checked rather than the old default, and turbo's profile note reports the real compiled-verify fence of 32,768 instead of the pre-2.7.0 number.
• A new build can't offer you an older one. Updates are ordered by build number, and the one derived for 2.7.1 came out below the 2.7.0 already in the wild, so a fresh 2.7.1 proposed 2.7.0 to itself. Fixed at the derivation, and the update feed now reads its number off the built app.

Still open

• With reasoning off, in a plain chat with no tools, Qwen 3.8 can still emit a stray tool call and end the turn early. Leave thinking on.

Upgrading

• App: Sparkle will offer 2.7.1 (build 2007001), or grab the DMG.
• CLI: pip install -U mtplx or brew upgrade mtplx.