In article , Eric Flesch
writes:

Two new pre-prints with contrasting results are out, kind of like the
scientific equivalent of a food fight. It's a hot topic, the CMB

Actually, quite cold, methinks. :-)

temperature as a function of redshift -- which, if true, makes any
static model untenable.

It would certainly make a static model more difficult than it is
already.

On 24 December arxiv:1212.5456 (accepted by A&A): "A precise and
accurate determination of the cosmic microwave background temperature
at z=0.89" by S. Muller et al determines a CMB temp of 5.08K for PKS
1830-211 at z=0.89, although they stated some assumptions,
particularly page 2 column 2 top "of great importance for our study"
that the emission is behind the absorbing gas.

On 27 December arxiv 1212.5625 (accepted by ApJ): "On Measuring the
CMB Temperature at Redshift 0.89" by M. Sato et al, determines a CMB
temp of 1.1 - 2.5K for this same galaxy! They pointedly assert that
high-resolution imaging shows that the absorbing gas covers at best
only part of the emitter.

There have been determinations of the CMB temperature at high redshift
in the past.

Appreciate if anyone can shed better light on this.

Not light, but maybe some microwaves. :-)

The general expectation is that the CMB temperature INCREASES with
redshift. How many papers find this, and how many find something else?

Not really relevant here, but IIRC, 1830-211 is a gravitational-lens
system. Any static model needs to QUANTITATIVELY explain the huge
amount of gravitational-lens data.