Alexa.com claiming has been retired on may 2016 and now site metrics is now the best way to measure your site traffics which you will activate with their subscription bill. So to claim your website with HTML, GOOGLE ANALYTIC and HTML UPLOAD is no longer active and if you don't use the site metric method your site traffics measured by Alexa will run down immediately.
Assuming your site traffics measured by Alexa was 10,0000 and you are not using site metric oprion, your site traffic will be reducing gradually without notice till 100 or below.
See Alexa retired claiming message "The Claim Your Site feature was retired in late May 2016. Is your site's contact information out of date on Alexa? Simply contact us and we'll be happy to help.
Note that we do still offer our Certified Site Metrics feature, which you can use to get your site's traffic directly measured. You can even use the directly measured traffic to get a more accurate ranking for your site."
So site metric for certification is now the method used by Alexa currently. So what do you have to say about this all webmasters?