## Before You Install
We recommend that you read through these prerequisites prior to installing the Opsview Monitor software. We also recommend that you use the automated installation method to install Opsview Monitor. When installing the Opsview Monitor software additional third-party software will be installed automatically, although some of the processes in this document may require that such software be installed first.
## Opsview Monitor Subscription
A valid Opsview Monitor subscription is required before you can complete the installation of the Opsview Monitor software, which will provide you with a Software Key.
## Before moving to Opsview Monitor 6.x
Please carefully read the documentation associated with the version of Opsview you are currently running and the methods available to start using Opsview Monitor 6.3.
[Supported Operating Systems](🔗)
#### First Installation
If this is the **first time you are installing Opsview Monitor**, please follow the steps in the [New Installation](🔗) pages.
#### Fully Qualified Domain Name required
To install Opsview version 6.x your server must have a Fully Qualified Domain Name (FQDN)
if not, you may receive the error "msg: '''opsview_host_domain'' cannot be empty!'"
#### Upgrade or Migration
If you need assistance with this process please contact the Opsview Customer Success team.
If you have customized your Apache configuration, you will need to convert and rewrite rules as part of the upgrade. See more information about converting Apache Rewrite Rules to Nginx Rewrite Rules, [here](🔗).
If you are running Version 6.3 or 6.4, please see [From 6.3 to 6.5](🔗).
If you are running Version 6.0, 6.1 or 6.2, please see [From 6.0, 6.1 or 6.2 to 6.3](🔗).
If you are running version 5.4.2, please see [From 5.4.x to 6.3](🔗)
Alternatively, if you would prefer to set up Opsview Monitor 6 on new hardware, please see [Migrating to New Hardware](🔗)
If you are unsure of whether to do an in-upgrade or a migration, please refer to [Moving to Opsview Monitor 6.5?](🔗) .