Umbraco-CMS/src/Umbraco.Web.UI/umbraco/js/umbracoUpgradeChecker.js

function umbracoCheckUpgrade(result) {
    if (result.UpgradeType.toLowerCase() != 'none') {
        if (UmbSpeechBubble == null) {
            InitUmbracoSpeechBubble();
        }
        var icon = 'info';
        if (result.UpgradeType.toLowerCase() == 'critical') {
            icon = 'error';
        }
        
        UmbSpeechBubble.ShowMessage(icon, 'Upgrade Available!', '<a style="text-decoration:none" target="_blank" href="' + result.UpgradeUrl + '">' + result.UpgradeComment + '</a>', true);
    }
        
}