use Exporter qw(import);

package Net::SNTP::Client;

our $VERSION = v5.18.2;           # Or higher...
our @ISA = qw(Exporter);
[download]

Please don't inherit from Exporter. It is not needed and has some unwanted side effects. use Exporter qw( import ); is sufficient. Remove the line our @ISA = qw(Exporter);. See also Re: Advice on style and Re^2: Advice on style.

Also note that our $VERSION = v5.18.2; looks like a misunderstanding. $VERSION is just an arbitary version number for your module. It has absolutely no relation to the perl version. If your code needs some minimum perl version, use use v5.18.2; or the more portable use 5.018002;.

And finally, move the package line up, preferably to the first line. Perl has no problem with a package line somewhere deep in the code, but it makes the intention clearer and is easier to read.

Alexander