Simpler example:

\usemodule[pgfplots]
\pgfplotsset{compat=newest}
\starttext
\starttikzpicture
   \startaxis
     [
       xlabel=$x$,
  ylabel={$f(x) = x^2 - x +4$}
     ]
     \addplot {x^2 - x +4};
   \stopaxis
\stoptikzpicture
\stoptext

Works with LMTX 2019.12.31 but fails with the most recent LMTX (same error 
as below) using the same pgfplots module.

Aditya

On Wed, 8 Apr 2020, Fabrice Couvreur wrote:

> Hi Henri,
> Sorry !
>
> \usemodule[pgfplots]
> \pgfplotsset{compat=newest}
> \starttext
> \starttikzpicture
>  \startaxis
>    [
>      xlabel=$x$,
> ylabel={$f(x) = x^2 - x +4$}
>    ]
>    \addplot {x^2 - x +4};
>  \stopaxis
> \stoptikzpicture
> \stoptext
>
>
> tex error       > tex error on line 5 in file pgfplotsbinary.data.code.tex:
> ! Undefined control sequence
>
> l.5 ...ode`\^0=11    \expandafter\xdef\csname pgfp@bin@\the\counter
> \endcsname{^0
>
>    }\advance\counter by1
> lua error:
>
> ?
>
>
> Le mer. 8 avr. 2020 à 12:40, Henri Menke <henrimenke@gmail.com> a écrit :
>
>> MINIMAL working example...
>>
>> Cheers, Henri
>>
>> On 08/04/20, 11:52, Fabrice Couvreur wrote:
>>> Hi Henri,
>>> This file works well with context but does not work with lmtx.
>>>
>>> \usemodule[pgfplots]
>>> \usemodule[pgfpltstable]
>>> \pgfplotsset{compat=newest}
>>> \starttext
>>> \starttikzpicture
>>> \startaxis[
>>>     title={\bf Relevé de notes chronologique},
>>>     ymajorgrids=true,
>>>     grid style={cyan!30},
>>>     ymin=0,
>>>     ymax=22,
>>>     xmin=0,
>>>     xmax=14,
>>>     x=1cm,
>>>     y=0.3cm,
>>>     axis x line =bottom,
>>>     axis y line =left,
>>>     axis on top=true,
>>>     axis line style =very thick,
>>>     tick align=outside,
>>>     tickwidth=0.12cm,
>>>     tick style=very thick,
>>>     xtick={\empty},
>>>     ytick={0,2,...,18,20},
>>>     extra x ticks={2,5,7,9,11,13},
>>>     extra x tick labels={octobre,novembre,janvier,mars,avril, juin},
>>>     extra x tick style={tick label style={rotate=45}},
>>>     extra tick style={tick style={draw=none}},
>>>     xlabel={Date},ylabel={Note},
>>>     xlabel={Date},ylabel={Effectif},
>>>  every axis x label/.style={
>>>  at={(ticklabel* cs:1.01)},
>>>  anchor=west,
>>>  },
>>>  every axis y label/.style={
>>>  at={(ticklabel* cs:1.01)},
>>>  anchor=south,
>>>  },
>>>  samples=1000,
>>> >=stealth,
>>> ]
>>> \addplot [color=green,only marks] coordinates {
>>>   (1,5)
>>>   (2,7)
>>>   (3,5)
>>>   (4,10)
>>>   (5,5)
>>>   (6,8)
>>>   (7,10)
>>>   (8,8)
>>>   (9,10)
>>>   (10,14)
>>>   (11,18)
>>>   (12,14)
>>>   (13,11)
>>> };
>>> \stopaxis
>>> \stoptikzpicture
>>> \stoptext
>>>
>>>
>>> open source     > level 7, order 88, name 'pgfplotsbinary.data.code.tex'
>>>
>>> tex error       > tex error on line 5 in file
>> pgfplotsbinary.data.code.tex:
>>> ! Undefined control sequence
>>>
>>> l.5 ...ode`\^0=11    \expandafter\xdef\csname pgfp@bin@\the\counter
>>> \endcsname{^0
>>>
>>>     }\advance\counter by1
>>> lua error:
>>>
>>> ?
>>>
>>>
>>>
>>> <empty file>
>>>
>>>
>>> The control sequence at the end of the top line of your error message was
>>> never
>>> \def'ed. You can just continue as I'll forget about whatever was
>> undefined.
>>>
>>>
>>> mtx-context     | fatal error: return code: 256
>>>
>>> TeX Output exited abnormally with code 1 at Wed Apr  8 11:49:56
>>>
>>>
>>> Le mer. 8 avr. 2020 à 11:21, Henri Menke <henrimenke@gmail.com> a écrit
>> :
>>>
>>>> Hi Fabrice,
>>>>
>>>> Could you provide a MWE, or maybe even open an issue on the bugtracker?
>>>> https://github.com/pgf-tikz/pgfplots/issues
>>>>
>>>> Cheers, Henri
>>>>
>>>> On 07/04/20, 14:22, Fabrice Couvreur wrote:
>>>>> Hi Henri,
>>>>> Thank you for answering me. We're entering an area that I don't
>> really
>>>> know. I
>>>>> replaced all ^^ by ^ but I'm not sure I understood. I now have the
>>>>> following message :
>>>>> Thank you
>>>>> Fabrice
>>>>>
>>>>> tex error       > tex error on line 5 in file
>>>> pgfplotsbinary.data.code.tex:
>>>>> ! Undefined control sequence
>>>>>
>>>>> l.5 \catcode`\^00=11 \expandafter\xdef\csname pgfp@bin@\the\counter
>>>>> \endcsname{^0
>>>>>
>>>>>    0}\advance\counter by1
>>>>> lua error:
>>>>>
>>>>> ?
>>>>>
>>>>>
>>>>>
>>>>> <empty file>
>>>>>
>>>>>
>>>>> The control sequence at the end of the top line of your error
>> message was
>>>>> never
>>>>> \def'ed. You can just continue as I'll forget about whatever was
>>>> undefined.
>>>>>
>>>>>
>>>>> mtx-context     | fatal error: return code: 256
>>>>>
>>>>> TeX Output exited abnormally with code 1 at Tue Apr  7 14:15:58
>>>>>
>>>>> Le mar. 7 avr. 2020 à 04:21, Henri Menke <henrimenke@gmail.com> a
>> écrit
>>>> :
>>>>>
>>>>>> The problem is that pgfplots uses the ^^ syntax to access
>> characters
>>>> but
>>>>>> this relies on ^ having catcode 7 which is not the case by default
>> in
>>>>>> ConTeXt.  I had a similar issue in PGF before and that was fixed by
>>>> just
>>>>>> replacing the ^^ syntax with the ascii code constants from
>>>>>> syst-ini.mkxl.
>>>>>>
>>>>>> Cheers, Henri
>>>>>>
>>>>>> On 06/04/20, 22:23, Fabrice Couvreur wrote:
>>>>>>> Hi,
>>>>>>> Still with the idea of using lmtx, I get a compilation error
>> when I
>>>> use
>>>>>>> pgfplots.
>>>>>>> Thank you.
>>>>>>> Fabrice
>>>>>>> ####################################################
>>>>>>> open source     > level 9, order 92, name
>>>> 'pgfplotsbinary.data.code.tex'
>>>>>>>
>>>>>>> tex error       > tex error on line 42 in file
>>>>>>> pgfplotsbinary.data.code.tex: ! Undefined control sequence
>>>>>>>
>>>>>>> l.42 \catcode`\ =11^^I\expandafter\xdef\csname pgfp@bin@
>>>>>>>
>>>>>>> \the\counter^^I\endcsname{^^20}\endgroup\advance\counter by1
>>>>>>> lua error:
>>>>>>>
>>>>>>> ?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> <empty file>
>>>>>>>
>>>>>>>
>>>>>>> The control sequence at the end of the top line of your error
>>>> message was
>>>>>>> never
>>>>>>> \def'ed. You can just continue as I'll forget about whatever was
>>>>>> undefined.
>>>>>>>
>>>>>>>
>>>>>>> mtx-context     | fatal error: return code: 256
>>>>>>>
>>>>>>> TeX Output exited abnormally with code 1 at Mon Apr  6 22:19:01
>>>>>>
>>>>>>>
>>>>>>
>>>>
>> ___________________________________________________________________________________
>>>>>>> If your question is of interest to others as well, please add an
>>>> entry
>>>>>> to the Wiki!
>>>>>>>
>>>>>>> maillist : ntg-context@ntg.nl /
>>>>>> http://www.ntg.nl/mailman/listinfo/ntg-context
>>>>>>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>>>>>>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>>>>>>> wiki     : http://contextgarden.net
>>>>>>>
>>>>>>
>>>>
>> ___________________________________________________________________________________
>>>>>>
>>>>>>
>>>>>>
>>>>
>> ___________________________________________________________________________________
>>>>>> If your question is of interest to others as well, please add an
>> entry
>>>> to
>>>>>> the Wiki!
>>>>>>
>>>>>> maillist : ntg-context@ntg.nl /
>>>>>> http://www.ntg.nl/mailman/listinfo/ntg-context
>>>>>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>>>>>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>>>>>> wiki     : http://contextgarden.net
>>>>>>
>>>>>>
>>>>
>> ___________________________________________________________________________________
>>>>>>
>>>>
>>>>>
>>>>
>> ___________________________________________________________________________________
>>>>> If your question is of interest to others as well, please add an
>> entry
>>>> to the Wiki!
>>>>>
>>>>> maillist : ntg-context@ntg.nl /
>>>> http://www.ntg.nl/mailman/listinfo/ntg-context
>>>>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>>>>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>>>>> wiki     : http://contextgarden.net
>>>>>
>>>>
>> ___________________________________________________________________________________
>>>>
>>>>
>>>>
>> ___________________________________________________________________________________
>>>> If your question is of interest to others as well, please add an entry
>> to
>>>> the Wiki!
>>>>
>>>> maillist : ntg-context@ntg.nl /
>>>> http://www.ntg.nl/mailman/listinfo/ntg-context
>>>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>>>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>>>> wiki     : http://contextgarden.net
>>>>
>>>>
>> ___________________________________________________________________________________
>>>>
>>
>>>
>> ___________________________________________________________________________________
>>> If your question is of interest to others as well, please add an entry
>> to the Wiki!
>>>
>>> maillist : ntg-context@ntg.nl /
>> http://www.ntg.nl/mailman/listinfo/ntg-context
>>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>>> wiki     : http://contextgarden.net
>>>
>> ___________________________________________________________________________________
>>
>>
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to
>> the Wiki!
>>
>> maillist : ntg-context@ntg.nl /
>> http://www.ntg.nl/mailman/listinfo/ntg-context
>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>> wiki     : http://contextgarden.net
>>
>> ___________________________________________________________________________________
>>
>