tkz-fct error after upgrade

Question

I can't make tkz-fct to produce the drawing of function. I have the impression it is caused by a recent update i made with tlmgr.

Gnuplot is working fine and I compile using --enable-write18.

Here is a mwe (this is just the test from the tkz-fct doc).

\documentclass{scrartcl}
\usepackage[usenames,dvipsnames]{xcolor}
\usepackage{tkz-fct}
\begin{document}
\begin{tikzpicture}[scale=1.25]
\tkzActivOff
\tkzInit[xmin=-5,xmax=5,ymax=2]
\tkzGrid
\tkzAxeXY
\tkzFct[color=red]{2*x**2/(x**2+1)}
\tkzActivOn
\end{tikzpicture}
\end{document}

And here is the log I get

(c:/texlive/2019/texmf-dist/tex/latex/jknapltx/ursfs.fd
File: ursfs.fd 1998/03/24 rsfs font definition file (jk)
) ( FP-EVAL ( FP-UPN
! Undefined control sequence.
<argument> \@xa 

l.11 \tkzFct[color=red]{2*x**2/(x**2+1)}

The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

! I don't know how to \FP@upn[].
\erroraction ... don't know how to \string #1[#2]}

l.11 \tkzFct[color=red]{2*x**2/(x**2+1)}

This error message was generated by an \errmessage
command, so I can't give any explicit help.
Pretend that you're Hercule Poirot: Examine all clues,
and deduce the truth by order and method.

! FP error: UPN stack is empty!.
\FP@errmessage #1->\errmessage {FP error: #1!}

l.11 \tkzFct[color=red]{2*x**2/(x**2+1)}

(That was another \errmessage.)

) ) ( FP-EVAL ( FP-UPN
! Undefined control sequence.
<argument> \@xb 

l.11 \tkzFct[color=red]{2*x**2/(x**2+1)}

The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

! I don't know how to \FP@upn[].
\erroraction ... don't know how to \string #1[#2]}

l.11 \tkzFct[color=red]{2*x**2/(x**2+1)}

(That was another \errmessage.)

! FP error: UPN stack is empty!.
\FP@errmessage #1->\errmessage {FP error: #1!}

l.11 \tkzFct[color=red]{2*x**2/(x**2+1)}

(That was another \errmessage.)

) ) ( FP-DIV ) ( FP-DIV ) [1

{c:/texlive/2019/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./test.aux) ) 
Here is how much of TeX's memory you used:
 28903 strings out of 492162
 603961 string characters out of 6129063
 752124 words of memory out of 5000000
 32871 multiletter control sequences out of 15000+600000
 535571 words of font info for 36 fonts, out of 8000000 for 9000
 1141 hyphenation exceptions out of 8191
 82i,7n,99p,10139b,861s stack positions out of 5000i,500n,10000p,200000b,80000s
<
c:/texlive/2019/texmf-dist/fonts/type1/public/amsfonts/cm/cmmi10.pfb><c:/texliv
e/2019/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb><c:/texlive/2019/tex
mf-dist/fonts/type1/public/amsfonts/cm/cmsy10.pfb>
Output written on test.pdf (1 page, 25654 bytes).
PDF statistics:
 23 PDF objects out of 1000 (max. 8388607)
 16 compressed objects within 1 object stream
 0 named destinations out of 1000 (max. 500000)
 13 words of extra memory for PDF output out of 10000 (max. 10000000)

Answer 1

yes you are right. The new version of tkz-base is incompatible with the version of tkz-fct.sty. There was a small problem uploading the new file on CTAN. You will have to wait a while before you can find the package on CTAN. Currently you will find the file v1.2 here

I think \tkzActivOff is no longer necessary with the latest version of TikZ.

\documentclass{standalone}
\usepackage[usenames,dvipsnames]{xcolor}
\usepackage{tkz-fct}
\begin{document}
\begin{tikzpicture}[scale=1.25]
%\tkzActivOff
\tkzInit[xmin=-5,xmax=5,ymax=2]
\tkzGrid
\tkzAxeXY
\tkzFct[color=red]{2*x**2/(x**2+1)}
%\tkzActivOn
\end{tikzpicture}
\end{document}