discourse/app/assets/javascripts/admin/controllers/admin_dashboard_controller.js

(function() {

  window.Discourse.AdminDashboardController = Ember.Controller.extend({
    loading: true,
    versionCheck: null,

    upToDate: (function() {
      if (this.versionCheck) {
        return this.versionCheck.latest_version === this.versionCheck.installed_version;
      } else {
        return true;
      }
    }).property('versionCheck'),

    updateIconClasses: (function() {
      var classes;
      classes = "icon icon-warning-sign ";
      if (this.get('versionCheck.critical_updates')) {
        classes += "critical-updates-available";
      } else {
        classes += "updates-available";
      }
      return classes;
    }).property('versionCheck'),

    priorityClass: (function() {
      if (this.get('versionCheck.critical_updates')) {
        return 'version-check critical';
      } else {
        return 'version-check normal';
      }
    }).property('versionCheck')
    
  });

}).call(this);