While researching the SharePoint Hybrid Search options that are being released, I happened upon this recently published support article: https://support.microsoft.com/en-us/kb/3080169. As you can see in the article, the hybrid search functionality will released for public preview on September 7th, 2015.
Back in July at the World Partner Conference, it was announced that the first preview of SharePoint 2016 was coming to the public in August. See this ITUnity article by Dan Holme for more information: http://www.itunity.com/article/sharepoint-2016-preview-released-august-2283
Knowing what was announced at WPC and now what was published by Microsoft in the support article, its a safe bet that the next release of SharePoint is just around the corner. Perhaps its on September 7th.
For further measure we know that Microsoft has been getting crafty with its numbers, Read: Windows 10’s Final Build Number delightfully clever. So releasing on September 7th would be clever as well since 9+7 = 16.
In any case we’ll see in under three short weeks