Biblatex/Biber problems with Texlive 2014 (no problems 2013)

Question

I have a TEX file which works OK with Texlive 2013 but is no longer working on 2014 (using OSX). It gives no error in the 2014 edition, but it does not produce the expected output.

Here is a minimal example that works with 2013 but not in 2014:

\documentclass[a4paper,12pt]{article}
\usepackage{hyperref}
\usepackage{fontspec}

\newfontfamily\arabicfont[Script=Arabic]{XB Zar}
\setmainfont[Numbers=OldStyle,Ligatures=Historic,Scale=1.3]{TeX Gyre Pagella}

\usepackage{polyglossia}
\setmainlanguage{english}
\setotherlanguage{arabic}

\usepackage[hyperref=true,natbib=true,style=authortitle,citestyle=authoryear-ibid,
sorting=nyt,autocite=footnote,backref=true,doi=false,isbn=false,url=false,
eprint=false,backend=biber,maxbibnames=30]{biblatex}

%% ARABIC NAME fields definition
\DeclareDatamodelFields[type=field, datatype=literal]{arabname}
\DeclareDatamodelFields[type=field, datatype=literal]{arabsurname}
\DeclareDatamodelFields[type=field, datatype=literal]{name}
\DeclareDatamodelFields[type=field, datatype=literal]{surname}
\DeclareDatamodelFields[type=field, datatype=literal]{rname}
\DeclareDatamodelFields[type=field, datatype=literal]{rsurname}
\DeclareDatamodelFields[type=field, datatype=literal]{lrname}
\DeclareDatamodelFields[type=field, datatype=literal]{hyear}
\DeclareDatamodelFields[type=field, datatype=literal]{sortaname}

%% ARABIC bibliography Driver
\DeclareBibliographyDriver{arabicname}{%
\usebibmacro{bibindex}%
\iffieldundef{name}{\textit{\printfield{rname}}}{
 \iffieldundef{surname}{\textit{\printfield{name}}}
 {\textit{\printfield{surname}}\addcomma\addspace
 \textit{\printfield{name}}}}
 \addspace
 \iffieldundef{arabsurname}{\printfield{arabname}}
 {\printfield{arabsurname}\addspace\printfield{arabname}}
 \addspace
 \printfield[parens]{year}
 \addcomma\addspace
 \usebibmacro{pageref}
}

\DeclareCiteCommand{\acite}
{}{\iffieldundef{name}{\printtext[bibhyperref]{\textit{\printfield{rname}}}}
{\iffieldundef{surname}{\printtext[bibhyperref]{\textit{\printfield{name}}}}
{\printtext[bibhyperref]{\textit{\printfield{name}}\addspace\textit{\printfield{surname}}}}}}
{}{}

\listfiles
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@arabicname{yusuf,
arabname = {\textarabic{الحجاج}},
arabsurname = {\textarabic{بن يوسف الثقفي}},
name = {al-Ḥajjāj},
surname = {\autocap{i}bn Yūsuf al-Thaqfī},
rname = {al-Hajjaj},
rsurname = {ibn Yusuf al-Thaqfi},
year = {661-714},
hyear = {40-95},
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}

This is a special text cite \acite{yusuf} 

\printbibliography
\end{document}

The output of the 2013 version is this:

And this is the 2014 output: