Will the primes also get fixed? In the latest standalone (I downloaded it minutes ago), I get the attached result running the same test file.

It seems that the primes are not yet fixed in mtx-context | current version: 2017.05.14 19:09 It requires, for example: \starttext Compare ${u_p}\hskip-.5em''$ and $u''_{\hskip-.63em p}$ with $u''$ \stoptext Best, Akira