According to the Maven documentation (http://maven.apache.org/ref/3.3.3/maven-model/maven.html), the following specifies the minimum required Maven version:
<prerequisites> <maven>[version]</maven> </prerequisites>
However, mvnvm seems to treat it as an absolute version. E.g. when the version is set to 2.2.1, mvnvm will download and run that version, even though a higher version is installed.