> Icinga 1.x and therefore require manual upgrade steps during pre-final
> milestone releases.
+> **Tip**
+>
+> Only install the IDO feature if your web interface or reporting tool requires
+> you to do so (for example, [Icinga Web](#setting-up-icinga-web) or [Icinga Web 2](#setting-up-icingaweb2)).
+> [Icinga Classic UI](#setting-up-icinga-classic-ui) does not use IDO as backend.
+
### <a id="configuring-ido-mysql"></a> Configuring IDO MySQL
#### <a id="setting-up-mysql-db"></a> Setting up the MySQL database
>
> On SuSE-based distributions the schema files are installed in
> `/usr/share/doc/packages/icinga2-ido-mysql/schema`.
+>
+> The Debian/Ubuntu packages put the schema files into
+> `/usr/share/icinga2-ido-mysql/schema`.
#### <a id="upgrading-mysql-db"></a> Upgrading the MySQL database
>
> On SuSE-based distributions the schema files are installed in
> `/usr/share/doc/packages/icinga2-ido-pgsql/schema`.
+>
+> The Debian/Ubuntu packages put the schema files into
+> `/usr/share/icinga2-ido-pgsql/schema`.
#### <a id="upgrading-postgresql-db"></a> Upgrading the PostgreSQL database
implements a query protocol that lets users query their Icinga instance for
status information. It can also be used to send commands.
+> **Tip**
+>
+> Only install the Livestatus feature if your web interface or addon requires
+> you to do so (for example, [Icinga Web 2](#setting-up-icingaweb2)).
+> [Icinga Classic UI](#setting-up-icinga-classic-ui) and [Icinga Web](#setting-up-icinga-web)
+> do not use Livestatus as backend.
+
The Livestatus component that is distributed as part of Icinga 2 is a
re-implementation of the Livestatus protocol which is compatible with MK
Livestatus.
for dumping the host dependencies as parents.
Special restrictions are noted specifically in the sections below.
+> **Tip**
+>
+> Chose your preferred interface. There's no need to install [Classic UI](#setting-up-icinga-classic-ui)
+> if you prefer [Icinga Web](#setting-up-icinga-web) or [Icinga Web 2](#setting-up-icingaweb2) for example.
+
### <a id="setting-up-icinga-classic-ui"></a> Setting up Icinga Classic UI
Icinga 2 can write `status.dat` and `objects.cache` files in the format that
Debian | icinga2-classicui
all others | icinga2-classicui-config icinga-gui
+> **Note**
+>
+> Debian packages require additional dependencies satisfied by the [debmon](http://www.debmong.org)
+> repository.
+
> **Note**
>
> On all distributions other than Debian you may have to restart both your web