Hi Hans, Last night I updated to th elatest beta LMTX (version 2019.10.28 18:57), and noticed that several things don't work as usual. I have not yet been able to find all the examples, but here is one in math: \definemathfence[abs][bar][command=yes,factor=auto] \starttext \startformula \sup_{t\in {\Bbb R}}\abs{f(t + T) - f(t)} \leq \epsilon. \stopformula \stoptext The above does not typeset and I have the following error message: tex error > tex error on line 7 in file ./bug-math.tex: ! This can't happen (mlist2) \stopforceddisplaymath ->\endgroup \stopimath \strc_math_box_stop ->\stopforceddisplaymath \egroup \d_strc_math_number_wid... \stopdisplaymath ...xpandafter \stopinnermath \fi \afterdisplayspace \egroup \strc_formulas_stop_formula ...formula \endcsname \dostoptagged \dostoptagge... l.7 \stopformula 1 \definemathfence[abs][bar][command=yes,factor=auto] 2 3 \starttext 4 5 \startformula 6 \sup_{t\in {\Bbb R}}\abs{f(t + T) - f(t)} \leq \epsilon. 7 >> \stopformula 8 9 \stoptext I'm broken. Please show this to someone who can fix me. mtx-context | fatal error: return code: 256 Thanks for your attention: OK PS: the PDF produced now with a colorful « error » is very nice… but the error messages are cryptic :-)