MTPLX 2.7.1

A bug-fix release. It clears the known-issues list 2.7.0 shipped with.

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.

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.