Wrong version of Log4J mentioned in the book?

[atais]

Hello,

So reading the chapter:
https://jaceklaskowski.gitbooks.io/mastering-apache-spark/content/spark-logging.html

there is Log4J2 mentioned and linked (docs, etc.)

However, I have found that Apache Spark (to my surprise) uses old Log4J1.
Here is the proof:
https://github.com/apache/spark/blob/master/pom.xml#L124

The configuration remained similar between those two, so the solution is still valid, but extending it may be misleading.