It looks like a bug has been introduced in the last update of biblatex. The code below used to output author's family names in small capitals, but not anymore?
\listfiles
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@book{Lame,
title={Théorie mathématique de l'élasticité des corps solides},
author={Lamé, Gabriel},
year={1852},
publisher={Bachelier},
address={Paris}
}
\end{filecontents}
\usepackage{biblatex}
\addbibresource{\jobname.bib}
\renewcommand{\mkbibnamelast}[1]{\textsc{#1}} % IMPORTANT LINE TO BE COMMENTED
\begin{document}
PLO \textsc{Plo} plo
\nocite{*}
\printbibliography
\end{document}
Is this what you observe as well?
biblatex.sty 2016/03/03 v3.3 programmable bibliographies (PK/JW/AB)
biblatex_.sty 2016/03/03 v3.3 programmable bibliographies (biber) (PK/JW/AB)
blx-dm.def
biblatex-dm.cfg
blx-compat.def 2016/03/03 v3.3 biblatex compatibility (PK/JW/AB)
biblatex_.def
standard.bbx 2016/03/03 v3.3 biblatex bibliography style (PK/JW/AB)
numeric.bbx 2016/03/03 v3.3 biblatex bibliography style (PK/JW/AB)
numeric.cbx 2016/03/03 v3.3 biblatex citation style (PK/JW/AB)
biblatex.cfg
english.lbx 2016/03/03 v3.3 biblatex localization (PK/JW/AB)
Best Answer
That's not bug but an intentional change in the name format system. You need to use other commands now:
(The next version will probably have some fallback system, but I recommend to change to the new commands anyway.)