Hi Hans,
with yesterday's beta, I get an error when calling a module:
tex error > tex error on line 65 in file /home/tas/texmf/tex/context/third/simpleslides/t-simpleslides.mkiv: ! Undefined control sequence
<argument> \syst_modules_setup
\syst_helpers_double_empty_one_spaced #1#2->#1 [{#2}][] <to be read again> \par l.65
55 \startmodule[simpleslides] 56 57 \unprotect 58 59 \setupmodule 60 [style=, 61 font=LatinModernSans, 62 size=17pt, 63 color=blue, 64 alternative=square] 65 >> 66 \usemodule 67 [simpleslides-fontsdefault] 68
Our module is trying to load submodules, in this case the file s-simpleslides-fontsdefault.mkiv. We had something similar a while ago, ConTeXt became more strict in the names it expected for modules, but that was resolved. An older beta (2015.11.19 19:13) works; I may have betas between these two on the computer in my office and can test those, if that helps. The definition of \syst_helpers_double_empty_one_spaced hasn't changed, AFAICS, and I couldn't see what caused the error in the changes of file-mod.mkvi.
All best
Thomas