Adding Post Meta Support for Alternate Versions

To add postmeta support for the BU Versions plugin, you must use the following filter to register the feature and the postmeta keys for the feature. During a clone, the data associated with the meta key will be copied. When the alternate version is "published" the data will overwrite the data stored in each meta key of the original.

<?php
function foo_register_alt_version_features( $features ) {
	$features['feature_name'] = array(
		'_foo_meta_key1',
		'_foo_meta_key2',
	);
	return $features;
}

add_filter( 'bu_alt_versions_feature_support', 'foo_register_alt_version_features' );