Problem with year and jourvol in Ukrainian localization in biblatex/biber

Question

I am using biblatex-gost package, gost-numeric style.

\documentclass[12pt,a4paper]{article}
\begin{filecontents}{\jobname.bib}
@book{samoylenko,
    title = {Диференціальні рівняння. Підручник},
    author = {А. М. Самойленко and М. О. Перестюк and І. О. Парасюк},
    location = {К.},
    publisher = {Либідь},
    year = {1994},
    pagetotal = {360},
}
@article{perestyuk,
    author = {Ю. М. Перестюк},
    title = {Розривні коливання в одній імпульсній системі},
    journal = {Нелінійні коливання},
    year = {2012},
    volume = {15},
    number = {4},
    pages = {494--503},
}
@book{hartman,
    langid = {english},
    title = {Ordinary Differential Equations},
    author = {P. Hartman},
    location = {Philadelphia},
    publisher = {Society for Industrial and Applied Mathematics},
    year = {2002},
    pagetotal = {612},
}
\end{filecontents}       
\usepackage[T2A]{fontenc}       
\usepackage[utf8]{inputenc}         
\usepackage[english,ukrainian]{babel} 
\usepackage[backend=biber,bibencoding=utf8,maxbibnames=999,style=gost-numeric,language=auto,autolang=other]{biblatex}
\addbibresource{\jobname.bib}

\DefineBibliographyStrings{ukrainian}{
and = {та},
number = {№},
page = {С\adddot},
pages = {С\adddot},
volume = {Т\addot},
%jourvol = {Т\addot},
}

\toggletrue{bbx:gostbibliography}
\usepackage[autostyle]{csquotes}

\begin{document}

\cite{samoylenko} \cite{perestyuk} \cite{hartman}

\printbibliography

\end{document}

Since there is no Ukrainian biblatex localization, based on this answer, I added the \DefineBibliographyStrings{ukrainian} command.

But even after that I have two problems:

1. Year field is missing in bibliography (only in Ukrainian books, English are fine).
2. jourvol instead of the desired Т. (only in Ukrainian articles).

I tried adding jourvol = {Т\addot}, but it produced the following error:

Undefined control sequence. \abx@sstr@jourvol

UPDATED TWICE: Here is a MWE displaying only the problem 1 (missing year field). When language is set to English everything works fine:

\documentclass[12pt,a4paper]{article}
\begin{filecontents}{\jobname.bib}
@book{samoylenko,
    title = {Диференціальні рівняння. Підручник},
    author = {А. М. Самойленко and М. О. Перестюк and І. О. Парасюк},
    location = {К.},
    publisher = {Либідь},
    year = {1994},
    pagetotal = {360},
}
\end{filecontents}       
\usepackage[T2A]{fontenc}       
\usepackage[utf8]{inputenc}         
\usepackage[english]{babel} 
\usepackage[backend=biber,bibencoding=utf8,maxbibnames=999,style=gost-numeric]{biblatex}
\addbibresource{\jobname.bib}

\toggletrue{bbx:gostbibliography}
\usepackage[autostyle]{csquotes}

\begin{document}

This was studied in \cite{samoylenko}.

\printbibliography

\end{document}

But I need 360 с. instead of 360 pp.. So I add Ukrainian language \usepackage[english,ukrainian]{babel}. Since my pdflatex is a little outdated, in does not contain a ukrainian.lbx file. So I create it manually with an empty content. Now I get

pages word can be translated using \DefineBibliographyStrings{ukrainian} command. But the year 1994 is gone.

Answer 1

As you mention your system is outdated and does not ship with ukrainian.lbx (that file has been available in biblatex since version 3.8a).

If you simply create an empty ukrainian.lbx you don't get bibliography strings (pages is one example - it is bold indicating the definition is missing), but you also don't get so-called bibliography extras. Amongst other things the bibliography extras define the date format. If the file does not contain definitions for the date, in some situation the date might be swallowed silently and will not be printed.

Ideally you would update your outdated TeX system to TeX live 2018. In that case Ukrainian works out of the box and everything should be fine. If you can't do that or you don't want to do that because your are close to a deadline, you have to find a work-around.

You could try and get ukrainian.lbx from https://github.com/plk/biblatex/commits/dev/tex/latex/biblatex/lbx/ukrainian.lbx and try if one of the older versions works for you. That is quite unlikely given that your system is so old now, the date handling changed a while ago, so the files are probably not compatible with your outdated system.

So your last resort is to write your own ukrainin.lbx for your outdated system. Take english.lbx, german.lbx or russian.lbx (you need the exact versions on your machine so we can be sure the file is compatible, usually you can find them with kpsewhich russian.lbx) as a basis and modify it as needed.