Often, users will take the version from Module->VERSION or $Module::VERSION and compare it to a number. This will issue a warning: 

package Module;
our $VERSION = "1.1_2";
my $new = Module->VERSION > 1.1;

Also, for modules that want to work properly on perls older than 5.10, leaving an underscore in the $VERSION will result in a use call throwing a warning.

In reply to Re^5: Why eval $version? by Haarg
in thread Why eval $version? by Aldebaran

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