According to table 1.31 and 1.32 supports PHP 7.2.x only. According to text: "The latest stable branch of MediaWiki (1.32) runs on any version of PHP 7.0.13 to PHP 7.2."
Shall I believe table or text?
Topic on Talk:Compatibility
The table is actually saying that 1.31, 1.32 and the master branch support PHP 7.0, 7.1 and 7.2 at the same time.