Upgrading a Minor Version (e.g. 2.5.3 to 2.6.1)
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Read the updated version of this page for Symfony 6.1 (the current stable version).
Upgrading a Minor Version (e.g. 2.5.3 to 2.6.1)
If you're upgrading a minor version (where the middle number changes), then you should not encounter significant backwards compatibility changes. For details, see the Symfony backwards compatibility promise.
However, some backwards-compatibility breaks are possible and you'll learn in a second how to prepare for them.
There are two steps to upgrading a minor version:
1) Update the Symfony Library via Composer
First, you need to update Symfony by modifying your composer.json file
to use the new version:
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{
"...": "...",
"require": {
"symfony/symfony": "2.6.*",
},
"...": "...",
}Next, use Composer to download new versions of the libraries:
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$ composer update symfony/symfonyDependency Errors
If you get a dependency error, it may simply mean that you need to upgrade other Symfony dependencies too. In that case, try the following command:
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$ composer update symfony/symfony --with-dependenciesThis updates symfony/symfony and all packages that it depends on, which will
include several other packages. By using tight version constraints in
composer.json, you can control what versions each library upgrades to.
If this still doesn't work, your composer.json file may specify a version
for a library that is not compatible with the newer Symfony version. In that
case, updating that library to a newer version in composer.json may solve
the issue.
Or, you may have deeper issues where different libraries depend on conflicting versions of other libraries. Check your error message to debug.
Upgrading other Packages
You may also want to upgrade the rest of your libraries. If you've done a
good job with your version constraints in composer.json, you can do
this safely by running:
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$ composer updateCaution
Beware, if you have some unspecific version constraints in your
composer.json (e.g. dev-master), this could upgrade some
non-Symfony libraries to new versions that contain backwards-compatibility
breaking changes.
2) Updating your Code to Work with the new Version
In theory, you should be done! However, you may need to make a few changes to your code to get everything working. Additionally, some features you're using might still work, but might now be deprecated. While that's just fine, if you know about these deprecations, you can start to fix them over time.
Every version of Symfony comes with an UPGRADE file (e.g. UPGRADE-2.7.md) included in the Symfony directory that describes these changes. If you follow the instructions in the document and update your code accordingly, it should be safe to update in the future.
These documents can also be found in the Symfony Repository.
