PHP 5.6.40-0+deb8u12

   PHP: Hypertext Preprocessor is a general-purpose programming language originally designed for web development.

PHP 5.6.30-0+deb8u1

   PHP: Hypertext Preprocessor is a general-purpose programming language originally designed for web development.

Apache 2.4.10 |Operating System:Debian

   The Apache HTTP Server, colloquially called Apache, is free and open-source cross-platform web server software, released under the terms of Apache License 2.0. Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

SPF

   The Sender Policy Framework (SPF) is an email-authentication technique which is used to prevent spammers from sending messages on behalf of your domain. With SPF an organisation can publish authorized mail servers.

Google Analytics

   Google Analytics is a web analytics service offered by Google that tracks and reports website traffic, currently as a platform inside the Google Marketing Platform brand.

Google Plus

   Google+ was an Internet-based social network owned and operated by Google. The network was launched on June 28, 2011 in the attempt to challenge other social networks and for a time linked other Google products like Blogger and YouTube.

SEO Robots : Allow to index and follow website links

   Meta robots tag is a tag that tells search engines what to follow and what not to follow.

Public Cache-Control

   Indicates that the response may be cached by any cache, even if the response would normally be non-cacheable (e.g. if the response does not contain a max-age directive or the Expires header).

Vary Header Accept-Encoding

   The Accept-Encoding request HTTP header advertises which content encoding, usually a compression algorithm, the client is able to understand. Using content negotiation, the server selects one of the proposals, uses it and informs the client of its choice with the Content-Encoding response header.

Character Encoding :UTF-8

   This website is using UTF-8 character encoding in HTML , character encoding is used to represent a repertoire of characters by some kind of encoding system.

Gzip Content-Encoding

   The Content-Encoding entity header is used to compress the media-type. When present, its value indicates which encodings were applied to the entity-body. It lets the client know how to decode in order to obtain the media-type referenced by the Content-Type header.