License File Structure

<?xml version="1.0" encoding="UTF-8"?>
<aps-3:key
    xmlns:aps-3="http://parallels.com/schemas/keys/aps/3"
    core:format="openfusion-3"
    xmlns:core="http://parallels.com/schemas/keys/core/3">
  <!-- Unique license number -->
  <core:key-number core:type="string">EXT.12345678</core:key-number>
  <!-- License version -->
  <core:key-version core:type="string">0001</core:key-version>
  <!-- Description of the license key: -->
  <core:description>
    <!-- * Key type ID -->
    <core:keytype>Acme Tools for Plesk</core:keytype>
    <!-- * List of the features enabled for the key -->
    <core:feature>Advanced Backup</core:feature>
    <core:feature>High Availability</core:feature>
  </core:description>
  <!-- Applicability to a certain third-party product and version -->
  <core:product core:type="string">ext-acme-tools</core:product>
  <core:version core:type="string">1.0</core:version>
  <!-- License validity timeframe and renewal information  -->
  <core:start-date core:type="date">instant</core:start-date>
  <core:expiration-date core:type="date">2016-04-12</core:expiration-date>
  <core:update-date core:type="date">2016-04-22</core:update-date>
  <!--
    License body wrapped as BASE64:
    Plesk extension should recognize the body as a valid key to unlock functionality
  -->
  <aps-3:key-body
      core:encoding="base64"
      core:type="binary">NCA4IDE1IDE2IDIzIDQy</aps-3:key-body>
... ... ...