Snippet to set minimum weight of UPS Package. WooCommerce UPS Shipping Plugin with Print Label - https://www.pluginhive.com/product/woocommerce-ups-shipping-plugin-with-print-label/

functions.php

/**
 * Snippet to set minimum weight of UPS Package.
 * Created at : 03 Dec 2018
 * Updated at : 03 Dec 2018
 * PluginHive Plugins : https://www.pluginhive.com/plugins/
 * Gist Link : https://gist.github.com/varun-pluginhive/a59ff76a71e33dd97303f931375d2ad5
 */
add_filter( 'ph_ups_generated_packages', function( $packages ){
	$min_weight	= 0.5;			// Minimum Weight of Package
	foreach( $packages as &$package ) {
		if( $min_weight > (double) $package['Package']['PackageWeight']['Weight'] ) {
			$package['Package']['PackageWeight']['Weight'] = $min_weight;
		}
	}
	return $packages;
} );