Pgfplots: Where do I find information what the newest version is (for `\pgfplotsset{compat=x.y}`)

Question

• I really tried to solve this question on my own: I must have missed the obvious answer.
• One can use \pgfplotsset{compat=x.y} to set used version of pgfplots.
• I thought that the version that is stated on CTAN or the manual cover page is the version that I can use within \pgfplotsset{compat=x.y}.
• But apparently, I am mistaken since the current version on CTAN is labeled 1.18.1 but I can use \pgfplotsset{compat=1.9} in my document.
• Question: Where does a naive user (meaning: no solution that requires looking at a log file) find out what is the newest version of pgfplots without using \pgfplotsset{compat=newest} (see here).

---

Update: I was stupid and confused 1.18 with 1.1.8! Thanks to user CarLaTeX for the help!

Answer 1

Run your document without \pgfplotsset{compat=...}

\documentclass{article}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis}
\addplot{x};
\end{axis}
\end{tikzpicture}
\end{document}

In the log you will get:

Package pgfplots Warning: running in backwards compatibility mode (unsuitable t
ick labels; missing features). Consider writing \pgfplotsset{compat=1.18} into 
your preamble.
 on input line 4.

The newest version is the one suggested in the log: \pgfplotsset{compat=1.18}.