On 25 Aug 2017, at 17:34 , Hans Hagen <pragma@wxs.nl> wrote:
> To: ntg-context@ntg.nl
> 
> On 8/25/2017 12:21 PM, Robert Blackstone wrote:
>> On 08/24/2017 10:57 AM, Robert Blackstone wrote:
>>>>> [...]
>>>>> %%%%%%%%%++++++MWE+++++++%%%%%%%%
>>>>> \usemodule[simplefonts]
>>>>> \setmainfont[Verdana]
>>>>> \setupbodyfont[10pt]
>> does not work anymore in mkiv versions later than july 2016.
>> 
>> Pablo Rodriguez helped me out:
>>>> 
>>>> Robert,
>>>> 
>>>> those commands now read:
>>>> 
>>>>   \definefontfamily[mainface][rm][Verdana]
>>>>   \setupbodyfont[mainface, 10pt]
>>>>   \starttext
>>>>   \input zapf
>>>>   \stoptext
>>>> 
>>>> I hope it helps,
>>>> 
>>>> Pablo
>> 
>> It does help but for the Law of the Conservation of Trouble (or Misery)
>> 
>> Having properly changed my font setup  ConTeXt stumbles upon things like:
>> 
>> “ 7~$\xrightarrow[none]$~6 progression ”
>> 
>> The error message is:  " ! Ma error: parameter \Umathquad\textstyle is not set."
>> 
>> How and where can I remedy this?
> This means that you haven't defined a math font so you need something:
> 
> \definefontfamily[mainface][rm][Verdana]
> \definefontfamily[mainface][tt][Courier]
> \definefontfamily[mainface][mm][Cambria]
> 
> or so, depending on what combination you want

Hi Hans,
Thanks for your reaction. Unfortunately it has not helped me for I have no idea how to set the parameter \Umathquad\textstyle. Just loading the fonts, as I believed you suggest in your mail, does not change anything: the compilation with a 2017 mkiv still stops at  “ 7~$\xrightarrow[none]$~6 progression ”.
However, when I use the older font calls, 
 \usemodule[simplefonts]
\setmainfont[Verdana]  
it compiles correctly files containing arrows ( $\xrightarrow[none]$ )  with the pre-2017 mkiv's . With my 2017 mkiv it still compiles correctly albeit not with the specified font but with latinmodern-math.otf. (Btw, I found the same behaviour for other fonts, such as: dejavu, times, palatino, bonum, lucidanova, lucida, garamond, libertine, gentium, xits, courier, and cambria.)  

For me the simplest solution would be to keep working with pre-2017 standalones for documents that contain these arrows (for musical tone- or chord-progressions )
But it intrigues me why some process that worked perfectly in many generations of mkiv has suddenly stopped working in the recent mkiv's. 

Best regards,

Robert Blackstone