Errore Suftesi 2.9.5. Appendici

Buonasera! Mi scuso per la nuova discussione. Ho aggiornato pochi minuti fa suftesi all’ultima versione e… quando compilo ottengo errore!
Nella fattispecie: `! Undefined control sequence.
l.2215 \AtBeginEnvironment
{appendices}{\appendix\mainmatter}
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.

`

Nella guida ho visto che ora esiste il nuovo pacchetto Appendix: ho provato ad inserirlo nel preambolo, seguendo anche le successive istruzioni sull’ambiente Appendices, ma l’errore resta. Dove sbaglio? Grazie
Gregorius

EMC:

`% !TEX encoding = UTF-8 Unicode
% !TEX TS-program = xelatex
% !BIB TS-program = biber

\documentclass[%
11pt,
%structure=book,
pagelayout=periodicalaureo,
version=cscreen,
style=smallcaps1,
liststyle=indented,
chapnumstyle=dotarabic,
tocstyle=leftpage,
tocchapfont=smallcaps,
titlefont=smallcaps,
chapfont=smallcaps,
secfont=smallcaps,
subsecfont=italic,
footnotestyle=superscript,
defaultfont=none,
greekfont=none,
%…other options
]{suftesi}
\usepackage{fontspec}
\setmainfont[%
Ligatures={TeX
%,Historic, Rare
}
]{Arial}
%
\usepackage{parallel}
\usepackage{xcolor}
\usepackage{mparhack}
\usepackage{multicol}
\usepackage{caption}
\usepackage{tikz}
\usepackage{synttree}
\usepackage{xytree}
\usepackage{epigraph}
\setlength{\beforeepigraphskip}{-1.5cm}
\setlength{\afterepigraphskip}{1cm}
\usepackage{lettrine}
\setcounter{DefaultLines}{3}
\usepackage[italian]{varioref}
\usepackage{multirow}
\usepackage{tabularx}
\usepackage{titlesec}
\titleformat{\paragraph}[runin]{\normalfont\bfseries}{\theparagraph.}{}{}[:]
\titlespacing{\paragraph}{\parindent}%
%{0pt} %elimina rientro%
{0pt}{.3em}[]
\usepackage{quoting}
\quotingsetup{font=small}
\usepackage{hyperref}
\hypersetup{hidelinks}
%
\usepackage{polyglossia}
\setmainlanguage{italian}
\setotherlanguage{german}
\setotherlanguage[variant=ancient]{greek}
\newfontfamily\greekfont[Script=Greek, Ligatures={TeX%,Historic, Rare%
}]{Times New Roman}
\newcommand{\greco}[1]{%
\begin{otherlanguage*}{greek}#1\end{otherlanguage*}}

% Bibliografia
\usepackage[style=italian]{csquotes}

\usepackage[backend=biber, style=philosophy-modern, classical=true, firstinits=true, autopunct=false, relatedformat=brackets, scauthors=false, scauthorsbib=false,scauthorscite=false, inbeforejournal=true, origfields=origed, shorthandintro=false, latinemph=true%
]{biblatex}

\renewcommand*{\finalnamedelim}{-}
\DefineBibliographyStrings{italian}{%
editor = {ed\adddot},
editors = {ed\adddot},
}
%\addbibresource{biblio.bib}

\DeclareMultiCiteCommand{\cites}%
{\cite}{\multicitedelim}
\DeclareMultiCiteCommand{\parencites}[\mkbibparens]%
{\parencite}{\multicitedelim}
\DeclareMultiCiteCommand{\footcites}[\mkbibfootnote]%
{\footcite}{\multicitedelim}

% Dati per titolo
\author{Zio Paperone}
\title{I racconti di Paperopoli}
\date{}

%————————————————–
%
% INIZIA IL DOCUMENTO
%
%————————————————–

\begin{document}

%———————————————-

\maketitle
\bookcolophon{All right reserved}{Typeset with \LaTeX{} with the \textsf{suftesi} class by Ivan Valbusa.
%Cover design by Ivan Valbusa.
}

(\greco{Ἄνδρα μοι ἔννεπε κτλ.})

(\greco{ἄνδρα})

%(\textgreek{ἄνδρα})

(ἄνδρα)

(\greco{Ἄνδρα μοι ἔννεπε κτλ.})

\greco{(ἄνδρα)}

L'\textit{Odissea} inizia con le parole \greco{(ἄνδρα)}

%———————————————
% Bibliografia
%
%\phantomsection % solo con hyperref
\printshorthands
\printbibliography
\tableofcontents
%************************

\end{document}`