Google Chrome will begin to mark all HTTP sites as "not secure" [googleblog.com] starting in July 2018. This is just a warning displayed in the URL bar and won't stop users from loading the pages:
For the past several years, we've moved toward a more secure web by strongly advocating that sites adopt HTTPS encryption. And within the last year, we've also helped users understand that HTTP sites are not secure by gradually marking [googleblog.com] a larger subset of HTTP pages as "not secure". Beginning in July 2018 with the release of Chrome 68, Chrome will mark all HTTP sites as "not secure".
Also at TechCrunch [techcrunch.com] and The Verge [theverge.com].