This simple MWE:

% arara: pdflatex



gives this error:

! Undefined control sequence.
l.4767   \ifdim\number\XeTeXversion
                                   \XeTeXrevision in<0.9995in %
! Emergency stop.
l.4767   \ifdim\number\XeTeXversion
                                   \XeTeXrevision in<0.9995in %
End of file on the terminal!

It worked since some time ago.

Is it a bug?

  • I think it was mentioned in chat or similar earlier today
    – daleif
    Nov 7, 2019 at 20:42
  • @daleif Ooooh, so is it a bug?
    – CarLaTeX
    Nov 7, 2019 at 20:42
  • Presumably, due to some of the updates to the kernel or the iftex collection
    – daleif
    Nov 7, 2019 at 20:43
  • 2
    The bug is actually in the class, but the next iftex version will avoid the problem. If you need it directly, ask me ;-) Nov 7, 2019 at 20:51
  • 1
    In the chat, David Carlisle reported that he has submitted the necessary fix to CTAN. Nov 9, 2019 at 19:58

1 Answer 1


It was a bug.

After waiting for fixing and updating my TeX distribution, now it works.

The versions of the packages now used are:

 *File List*
ltugboat.cls    2019-11-09 v2.22 TUGboat journal class
 article.cls    2019/10/25 v1.4k Standard LaTeX document class
  size10.clo    2019/10/25 v1.4k Standard LaTeX file (size option)
  mflogo.sty    1999/03/10 v2.0 LaTeX package for Metafont and MetaPost logos
hyperref.sty    2019/11/10 v7.00c Hypertext links for LaTeX
 ltxcmds.sty    2016/05/16 v1.23 LaTeX kernel commands for general use (HO)
   iftex.sty    2019/11/07 v1.0c TeX engine tests
pdftexcmds.sty    2019/07/25 v0.30 Utility functions of pdfTeX for LuaTeX (HO)
infwarerr.sty    2016/05/16 v1.4 Providing info/warning/error messages (HO)
ifluatex.sty    2019/10/25 v1.5 ifluatex legacy package. Use iftex instead.
   ifpdf.sty    2019/10/25 v3.4 ifpdf legacy package. Use iftex instead.
  keyval.sty    2014/10/28 v1.15 key=value parser (DPC)
kvsetkeys.sty    2016/05/16 v1.17 Key value parser (HO)
etexcmds.sty    2016/05/16 v1.6 Avoid name clashes with e-TeX commands (HO)
kvdefinekeys.sty    2016/05/16 v1.4 Define keys (HO)
pdfescape.sty    2016/05/16 v1.14 Implements pdfTeX's escape features (HO)
 hycolor.sty    2016/05/16 v1.8 Color options for hyperref/bookmark (HO)
xcolor-patch.sty    2016/05/16 xcolor patch
 hopatch.sty    2016/05/16 v1.3 Wrapper for package hooks (HO)
letltxmacro.sty    2016/05/16 v1.5 Let assignment for LaTeX macros (HO)
 auxhook.sty    2016/05/16 v1.4 Hooks for auxiliary files (HO)
kvoptions.sty    2016/05/16 v3.12 Key value format for package options (HO)
  pd1enc.def    2019/11/10 v7.00c Hyperref: PDFDocEncoding definition (HO)
 intcalc.sty    2016/05/16 v1.2 Expandable calculations with integers (HO)
hyperref.cfg    2002/06/06 v1.2 hyperref configuration of TeXLive
     url.sty    2013/09/16  ver 3.4  Verb mode for urls, etc.
  bitset.sty    2016/05/16 v1.2 Handle bit-vector datatype (HO)
bigintcalc.sty    2016/05/16 v1.4 Expandable calculations on big integers (HO)
atbegshi.sty    2016/06/09 v1.18 At begin shipout hook (HO)
 hpdftex.def    2019/11/10 v7.00c Hyperref driver for pdfTeX
atveryend.sty    2016/05/16 v1.9 Hooks at the very end of document (HO)
rerunfilecheck.sty    2016/05/16 v1.8 Rerun checks for auxiliary files (HO)
uniquecounter.sty    2016/05/16 v1.3 Provide unlimited unique counter (HO)
 nameref.sty    2019/09/16 v2.46 Cross-referencing by name of section
refcount.sty    2016/05/16 v3.5 Data extraction from label references (HO)
gettitlestring.sty    2016/05/16 v1.5 Cleanup title references (HO)

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