This are updated instructions from January 2017 regarding post published in December 2015! Previous comments were deleted!

Update 2017-01-26
Added new variables in Apache configuration so no more copying of DLL’s.

Goal was to setup latest QGIS Server LTR  (2.14.x) on Windows 10 for use with Extended QGIS Web Client (EQWC). Main components needed for this are (minimum required versions):

  1. Apache 2.4
  2. PHP 5.5
  3. PostgresSQL 9.3
  4. QGIS Server LTR 2.14

PostgreSQL, Apache and PHP

All these are easiest installed by using PostGreSQL install. In Stack Builder add Apache/PHP option as seen on picture:

I installed this in c:/Apache24 folder

Test for Apache and PHP

QGIS Server LTR 2.14

Download 64 bit OSGeo4W installer . Choose advanced installation, from web and then select QGIS Server LTR from Web part and qscintilla from libs.

Apache configuration

Edit httpd.conf file (in my case its in C:\Apache24\apache\conf)

ScriptAlias

change line:

ScriptAlias /cgi-bin/ "C:\Apache24/apache/cgi-bin/"

to:

ScriptAlias /cgi-bin/ "c:/OSGeo4W64/apps/qgis-ltr/bin/"

QGIS Server configuration

change part:

<Directory "c:/Apache24/apache/cgi-bin">
 AllowOverride None
 Options None
 Require all granted
 </Directory>

to:

<Directory "c:\OSGeo4W64\apps\qgis-ltr\bin">
SetHandler cgi-script
AllowOverride None
Options ExecCGI
Order allow,deny
Allow from all
Require all granted
</Directory>

Cgi handler

change line:

#AddHandler cgi-script .cgi

to:

AddHandler cgi-script .cgi .pl .exe

Add this to fix performance issue

insert at bottom of http.conf:

# Apparently this fixes an issue with Apache 2.4.6 on Windows hanging
# when serving requests from Internet Explorer 10/11.
# see
http://stijndewitt.wordpress.com/2014/01/10/apache-hangs-ie11/
AcceptFilter http none
AcceptFilter https none

Variables

insert at bottom of http.conf:

SetEnv GDAL_DATA "C:\OSGeo4W64\share\gdal"
SetEnv QGIS_AUTH_DB_DIR_PATH "C:\OSGeo4W64\apps\qgis-ltr\resources"
SetEnv PYTHONHOME "C:\OSGeo4W64\apps\Python27"
SetEnv PATH "C:\OSGeo4W64\bin;C:\OSGeo4W64\apps\qgis-ltr\bin;C:\OSGeo4W64\apps\grass\grass-@grassversion@\bin;C:\OSGeo4W64\apps\grass\grass-@grassversion@\lib;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem”
SetEnv QGIS_PREFIX_PATH "C:\OSGeo4W64\apps\qgis-ltr"
SetEnv QT_PLUGIN_PATH "C:\OSGeo4W64\apps\qgis-ltr\qtplugins;C:\OSGeo4W64\apps\qt4\plugins"

That completes Apache configuration.

Test

Restart Apache server (EnterpriseDB ApachePHP from Services) and open a GetCapabilities request to QGIS Server

http://localhost:8080/cgi-bin/qgis_mapserv.fcgi.exe?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetCapabilities

You should receive standard WMS Capabilities XML response from QGIS Server.

Extra setup for Extended QGIS Web Client

Enable Apache rewrite module and insert Rewrite rules in httpd.conf

LoadModule rewrite_module modules/mod_rewrite.so

RewriteEngine On
RewriteRule ^/proxy/(.+)$ /gisapp/admin/qgisproxy.php?map=$1.qgs [QSA,PT]
RewriteRule ^/gisapp/([^\.]+)$ /gisapp/index.php [PT]

Restart Apache server. To finish setup of Extended QGIS Web Client go to GitHub repository and Wiki pages and continue with database and user setup.