Pgfgantt backwards incompatibility

Question

I just installed TeXLive 2013 in favor of TeXLive 2012, and there seems to be a backwards incompatibility with the way milestones are rendered in pgfgantt. In TeXLive 2012, my Gantt chart code is rendered as follows:

However, in TeXLive 2013, after fixing some apparently deprecated attributes (such as milestone width), it is rendered as follows:

I like the original milestone signs much better, but I haven't been able to figure out how to get back the original milestone style. Does anyone know how to do this?

The code is essentially: (I've stripped it down to a MWE)

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfgantt}

\begin{document}
\begin{ganttchart}[inline,vgrid]{1}{17}
  \gantttitlelist{1,...,17}{1} \\
  \ganttbar{$(1,2)$}{1}{15} 
  \ganttbar{$(1,3)$}{1}{10} 
  \ganttbar{$(4,6)$}{11}{13}
  \ganttbar{$(1,4)$}{1}{8}
  \ganttbar{$(4,5)$}{9}{14} \\
  \ganttmilestone{$1$}{0}
  \ganttmilestone{$4$}{8}
  \ganttmilestone{$2$}{15}
\end{ganttchart}
\end{document}

Answer 1

Just for reference, this is what your MWE produces:

Compiling with TexLive 2012 (which uses pgfgantt 2012/01/25 v3.0):

Compiling with TexLive 2013 (which uses pgfgantt 2013/06/01 v4.0):

As you can see, the milestones have the same shape, and apparently the only difference is the background grid. So, either your previous version of pgfgantt was even older, or you reduced too much the MWE and eliminated some code which affected the milestone shapes.

Anyway, I compared the code of pgfgantt.sty for both versions, and saw that it completely changed the way it deals with these kind of shapes. In the new version, proper tikz node shapes are created, and lots of tiny details are managed through pgf keys.

Using these keys, you can recover your previous milestones by simply adding to your preamble:

 \pgfkeys{
   /pgfgantt/milestone inline label node/.style={
       shape=rectangle, draw=black, fill=white, anchor=north
       }
 }

and get: