Hi,

I've just created an OBS repo[1] for syslog-ng 3.6.x series (current version: 3.6.4 [2] ).
This means that this is not an official Debian/Ubuntu APT repository but one hosted by OBS.

List of supported OSs (i386/amd64):
* Debian 7.0
* Debian 8.0
* Ubuntu 12.04
* Ubuntu 14.04
* Ubuntu 14.10
* Ubuntu 15.04


Install
-------

1. get release key
wget -qO - http://download.opensuse.org/repositories/home:/laszlo_budai:/syslog-ng-3.6/Debian_8.0/Release.key | sudo apt-key add -

2. add repo to APT sources
eg.: /etc/apt/sources.list.d/syslog-ng-obs.list
deb http://download.opensuse.org/repositories/home:/laszlo_budai:/syslog-ng-3.6/Debian_8.0 ./

Then `apt-get update` and `apt-get install syslog-ng-core=3.6.4-1`

You can replace Debian_8.0 to
 * Debian_7.0
 * xUbuntu_12.04, 
 * xUbuntu_14.04
 * xUbuntu_14.10
 * xUbuntu_15.04

(`x` before Ubuntu is not a typo ;-) )

Available packages:
 * syslog-ng-core
 * syslog-ng-dbg
 * syslog-ng-dev
 * syslog-ng-mod-amqp
 * syslog-ng-mod-geoip
 * syslog-ng-mod-graphite
 * syslog-ng-mod-json
 * syslog-ng-mod-mongodb
 * syslog-ng-mod-redis
 * syslog-ng-mod-riemann
 * syslog-ng-mod-smtp
 * syslog-ng-mod-sql
 * syslog-ng-mod-stomp


Links
--------
[1] https://build.opensuse.org/project/show/home:laszlo_budai:syslog-ng-3.6
[2] https://github.com/balabit/syslog-ng/releases/tag/syslog-ng-3.6.4

regards,
Laszlo Budai
(lbudai)