## Instructions

Typically, there are seven steps involved in upgrading to a newer version of Trac:

### 1. Bring your server off-line

It is not a good idea to update a running server: the server processes may have parts of the current packages cached in memory, and updating the code will likely trigger internal errors.

Although a database backup will be implicitly created by default when upgrading the environment, it is always a good idea to perform a full backup of the environment using the hotcopy command before beginning.

### 2. Update the Trac Code

Get the new version as described in TracInstall, or your operating system specific procedure.

If you already have a 0.12 version of Trac installed via easy_install, it might be easiest to also use easy_install to upgrade your Trac installation:

easy_install --upgrade Trac==1.0


If you do a manual (not operating system-specific) upgrade, you should also stop any running Trac servers before the installation. Doing "hot" upgrades is not advised, especially on Windows (#7265).

You may also want to remove the pre-existing Trac code by deleting the trac directory from the Python lib/site-packages directory, or remove Trac .egg files from former versions. The location of the site-packages directory depends on the operating system and the location in which Python was installed. However, the following locations are typical:

• on Linux: /usr/lib/python2.X/site-packages
• on Windows: C:\Python2.X\lib\site-packages
• on MacOSX: /Library/Python/2.X/site-packages

You may also want to remove the Trac cgi-bin, htdocs, templates and wiki-default directories that are commonly found in a directory called share/trac. The exact location depends on your platform. This cleanup is not mandatory, but makes it easier to troubleshoot issues later on, as your installation is uncluttered by code or templates from a previous release that is not used anymore. As usual, make a backup before actually removing things.

### 3. Upgrade the Trac Environment

Environment upgrades are not necessary for minor version releases unless otherwise noted.

After restarting, Trac should show the instances which need a manual upgrade via the automated upgrade scripts to ease the pain. These scripts are run via trac-admin:

trac-admin /path/to/projenv upgrade


This command will do nothing if the environment is already up-to-date.

Note that a backup of your database will be performed automatically prior to the upgrade. This feature is relatively new for PostgreSQL or MySQL databases, so if it fails, you will have to backup the database manually. Then, to perform the actual upgrade, run:

trac-admin /path/to/projenv upgrade --no-backup


### 4. Update the Trac Documentation

By default, every Trac environment includes a copy of the Trac documentation for the installed version. However, to keep the included documentation in sync with the installed version of Trac, use the following trac-admin command to upgrade the documentation:

trac-admin /path/to/projenv wiki upgrade


Note that this procedure will leave your WikiStart page intact.

### 5. Refresh static resources

If you have set up a web server to give out static resources directly (accessed using the /chrome/ URL) then you will need to refresh them using the same command:

trac-admin /path/to/env deploy /deploy/path


this will extract static resources and CGI scripts (trac.wsgi, etc) from new Trac version and its plugins into /deploy/path.

Some web browsers (IE, Opera) cache CSS and Javascript files aggressively, so you may need to instruct your users to manually erase the contents of their browser's cache, a forced refreshed (<F5>) should be enough.

### 6. Steps specific to a given Trac version

#### Upgrading from Trac 0.12 to Trac 1.0

##### Python 2.4 no longer supported

Upgrade Python to at least 2.5, but not 3.0.

##### Obsolete Plugins

Trac has added functionality equivalent to the following plugins:

The plugins should be removed when upgrading Trac to 1.0.

##### Subversion components not enabled by default for new installations

The Trac components for Subversion support are no longer enabled by default. To enable the svn support, you need to make sure the tracopt.versioncontrol.svn components are enabled, for example by setting the following in the TracIni:

[components]
tracopt.versioncontrol.svn.* = enabled


The upgrade procedure should take care of this and change the TracIni appropriately, unless you already had the svn components explicitly disabled.

##### Attachments migrated to new location

Another step in the automatic upgrade will change the way the attachments are stored. Create a backup of the attachments directory before upgrading. In case the attachments directory contains some files which are not attachments, the last step of the migration to the new layout will fail: the deletion of the now unused attachments directory can't be done if there are still files and folders in it. You may ignore this error, but better to move them elsewhere and remove the attachments directory manually. The attachments themselves are now all located in your environment below the files/attachments directory.

##### Behavior of [ticket] default_owner changed

Prior to 1.0, the owner field of new tickets always defaulted to [ticket] default_owner when the value was not empty. If the value was empty, the owner field defaulted to to the Component's owner. In 1.0 and later, the default_owner must be set to < default > to make new tickets default to the Component's owner. This change allows the default_owner to be set to an empty value if no default owner is desired.

#### Upgrading from Trac 0.11 to Trac 0.12

##### Python 2.3 no longer supported

The minimum supported version of Python is now 2.4.

##### SQLite v3.x required

SQLite v2.x is no longer supported. If you still use a Trac database of this format, you'll need to convert it to SQLite v3.x first. See PySqlite#UpgradingSQLitefrom2.xto3.x for details.

##### ​PySqlite 2 required

PySqlite 1.1.x is no longer supported. Please install 2.5.5 or later if possible, see Trac database upgrade below.

##### Obsolete Plugins

Trac has added functionality equivalent to the following plugins:

The plugins should be removed when upgrading Trac to 0.12.

##### Multiple Repository Support

The latest version includes support for multiple repositories. If you plan to add more repositories to your Trac instance, please refer to TracRepositoryAdmin#Migration.

This may be of interest to users with only one repository, since there is now a way to avoid the potentially costly resync check at every request.

##### Resynchronize the Trac Environment Against the Source Code Repository

Each Trac environment must be resynchronized against the source code repository in order to avoid errors such as "No changeset ??? in the repository" while browsing the source through the Trac interface:

trac-admin /path/to/projenv repository resync '*'

##### Improved repository synchronization

In addition to supporting multiple repositories, there is now a more efficient method for synchronizing Trac and your repositories.

While you can keep the same synchronization as in 0.11 adding the post-commit hook as outlined in TracRepositoryAdmin#Synchronization and TracRepositoryAdmin#ExplicitSync will allow more efficient synchronization and is more or less required for multiple repositories.

Note that if you were using the trac-post-commit-hook, you're strongly advised to upgrade it to the new hook documented in the above references and here, as the old hook will not work with anything else than the default repository and even for this case, it won't trigger the appropriate notifications.

### 7. Restart the Web Server

If you are not running CGI, reload the new Trac code by restarting your web server.

## Known Issues

### Customized Templates

Trac supports customization of its Genshi templates by placing copies of the templates in the <env>/templates folder of your environment or in a common location specified in the [inherit] templates_dir configuration setting. If you choose to do so, be aware that you will need to repeat your changes manually on a copy of the new templates when you upgrade to a new release of Trac (even a minor one), as the templates will likely evolve. So keep a diff around.

The preferred way to perform TracInterfaceCustomization is to write a custom plugin doing an appropriate ITemplateStreamFilter transformation, as this is more robust in case of changes: we usually won't modify element ids or change CSS classes, and if we have to do so, this will be documented in the TracDev/ApiChanges pages.

### ZipImportError

Due to internal caching of zipped packages, whenever the content of the packages change on disk, the in-memory zip index will no longer match and you'll get irrecoverable ZipImportError errors. Better anticipate and bring your server down for maintenance before upgrading. See #7014 for details.

trac-admin will not delete or remove default wiki pages that were present in a previous version but are no longer in the new version.

### Trac database upgrade

A known issue in some versions of PySqlite (2.5.2-2.5.4) prevents the trac-admin upgrade script from successfully upgrading the database format. It is advised to use either a newer or older version of the sqlite python bindings to avoid this error. For more details see ticket #9434.

### Parent dir

If you use a Trac parent env configuration and one of the plugins in one child does not work, none of the children will work.

## Related topics

Upgrading Python to a newer version will require reinstallation of Python packages: Trac itself of course, but also easy_install, if you've been using that. If you are using Subversion, you'll also need to upgrade the Python bindings for svn.

#### Windows and Python 2.6

If you've been using CollabNet's Subversion package, you may need to uninstall that in favor of Alagazam, which has the Python bindings readily available, see TracSubversion. That package works without tweaking.

### Changing Database Backend

The TracMigratePlugin on trac-hacks.org has been written to assist in migrating between SQLite, MySQL and PostgreSQL databases.

### Upgrading from older versions of Trac

For upgrades from versions older than Trac 0.10, refer first to wiki:0.10/TracUpgrade#SpecificVersions.