Q:

How only one x tick label could be changed in pfgplots?

I'd like to have this x axis using pgfplots:
,
where only number 4 has + as tick label.
I could easily make all numbers have + tick label by adding xticklabel=\pgfmathprintnumber{\tick}\,+,
\documentclass[12pt,tikz]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.9}
\begin{document}
\begin{tikzpicture}
%If you do not like this style just delete it.
%But you will need to add to \addplot[color] this "line width=2pt, rounded corners" to change line width and add rounded corners.
\tikzset{ every path/.style={line width=2pt, rounded corners}}
\begin{axis}[
title style={text width=10cm,align=center,font=\small},
width=9cm,
height=6cm,
ymin=2,
xtick={0,...,4},
xticklabel=\pgfmathprintnumber{\tick}\,+,
]
\addplot[blue] coordinates {(0,1) (1,2) (3,4) (4,2)};
\end{axis}
\end{tikzpicture}
\end{document}

What is the way to do it?

A:

Use xticklabels={0, 1, 2, 3, 4+},:
\documentclass[12pt,tikz]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.9}
\begin{document}
\begin{tikzpicture}
%If you do not like this style just delete it.
%But you will need to add to \addplot[color] this "line width=2pt, rounded corners" to change line width and add rounded corners.
\tikzset{ every path/.style={line width=2pt, rounded corners}}
\begin{axis}[
title style={text width=10cm,align=center,font=\small},
width=9cm,
height=6cm,
ymin=2,
xtick={0,...,4},
xticklabels={0, 1, 2, 3, 4+},
]
\addplot[blue] coordinates {(0,1) (1,2) (3,4) (4,2)};
\end{axis}
\end{tikzpicture}
\end{document}

