• Make sure that the iTop configuration file (config-itop.php in conf/production) is not read-only,
• Point your web browser to http(s)://location_of_itop/setup and follow the on-screen instructions.

The step by step wizard to install the application is reused for an upgrade with a few differences.

The first step checks the consistency of the configuration and the prerequisites for MySQL, PHP and optional PHP extensions. It may fail during an upgrade as it can be more restrictive than it was in a previous version.
For example after 2.5.0, prerequisites on MySQL and PHP will change.

The second step of the update, summarized information already provided in a previous setup related to database connection and propose by default to create an iTop backup before the application and database upgrade.

The third step of an upgrade prompts your for several miscellaneous information which can still be changed during an upgrade:

The following steps of the update wizard allow you to add modules, but you cannot change/remove already selected ones.

You cannot remove modules installed at initial setup but you can add some.

In most cases, that has been set at initial setup time and can not be changed

If you now wants to manage Tickets in iTop, check the install for possible options.
You cannot switch between Simple and ITIL Compliant Ticket Management once a choice has been made in a previous Setup, nor dis-activate the Ticket Management module.

If you now wants to manage Changes in iTop, check the install for possible options.
You cannot switch between Simple and ITIL Compliant Change Management once a choice has been made in a previous Setup, nor dis-activate the Change Management

You cannot remove modules installed at initial setup but you can add some.

If you have added Modules/Extensions, they can be installed but not removed, at this step of the upgrade process.

Once all the choices are made, a summary is displayed. You can drill down to check your choices by clicking on the “plus” button for each section.

To start the actual upgrade of iTop, click on the “Install !” button.

The progress of the upgrade is displayed with a moving progress bar.

Once the upgrade is done you get:

Congratulation, you’ve successfully upgraded iTop!

At the beginning of a Setup, iTop is moved in read-only, by the means of a file named .readonly under <itop>/data. Application is no more writable, as the database structure might be drastically modified.
Then during the datamodel compilation, iTop is moved to maintenance mode, by the means of a file named .maintenance in the same place. Because during this phase there is no more a valid iTop code which could be used, even for a read mode.
This mechanism applies:

• on Setup,
• when iTop Hub pushes an extension,
• when the ITSM Designer pushes a new datamodel (for Combodo's customers)
• on an Application upgrade.