updating symfony 2.6 to 2.7 - php

Question

im trying to update symfony 2.6 to 2.7
i've changed in my composer.json to 2.7 version
"symfony/symfony": "2.7.*"
im running
composer update symfony/symfony --with-dependencies
and getting this error
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Conclusion: don't install symfony/symfony v2.7.41
- Conclusion: don't install symfony/symfony v2.7.40
........
- Conclusion: don't install symfony/symfony v2.7.2
- Conclusion: don't install symfony/symfony v2.7.1
- don't install symfony/asset v3.4.4|don't install symfony/symfony v2.7.0
- don't install symfony/symfony v2.7.0|remove symfony/asset v3.4.4
- don't install symfony/symfony v2.7.0|don't install symfony/asset v3.4.4
- Installation request for symfony/symfony 2.7.* -> satisfiable by symfony/symfony[v2.7.0, v2.7.1, v2.7.10, v2.7.11, v2.7.12, v2.7.13, v2.7.14, v2.7.15, v2.7.16, v2.7.17, v2.7.18, v2.7.19, v2.7.2
, v2.7.20, v2.7.21, v2.7.22, v2.7.23, v2.7.24, v2.7.25, v2.7.26, v2.7.27, v2.7.28, v2.7.29, v2.7.3, v2.7.30, v2.7.31, v2.7.32, v2.7.33, v2.7.34, v2.7.35, v2.7.36, v2.7.37, v2.7.38, v2.7.39, v2.7.4, v
2.7.40, v2.7.41, v2.7.5, v2.7.6, v2.7.7, v2.7.8, v2.7.9].
- Installation request for symfony/asset (locked at v3.4.4) -> satisfiable by symfony/asset[v3.4.4].
i dont understand what it wants from me
here is my composer.json
{
"name": "symfony/framework-standard-edition",
"license": "MIT",
"type": "project",
"description": "The \"Symfony Standard Edition\" distribution",
"autoload": {
"psr-0": { "": "src/", "SymfonyStandard": "app/" }
},
"require": {
"php": ">=5.3.9",
"doctrine/doctrine-bundle": "~1.2",
"doctrine/orm": "~2.2,>=2.2.3",
"incenteev/composer-parameter-handler": "~2.0",
"sensio/distribution-bundle": "~3.0",
"sensio/framework-extra-bundle": "~3.0",
"symfony/assetic-bundle": "~2.3",
"symfony/monolog-bundle": "~2.4",
"symfony/swiftmailer-bundle": "~2.3",
"symfony/symfony": "2.7.*",
"twig/extensions": "~1.0",
"gedmo/doctrine-extensions": "^2.3.1",
"stof/doctrine-extensions-bundle": "dev-master",
"symfony/dom-crawler": "~2.6",
"friendsofsymfony/user-bundle": "~2.0#dev",
"ircmaxell/password-compat": "^1.0",
"helios-ag/fm-elfinder-bundle": "~5",
"egeloen/ckeditor-bundle": "^3.0",
"vich/uploader-bundle": "^1.4",
"google/apiclient": "~2.0",
"masih/youtubedownloader": "^2.8"
},
"require-dev": {
"sensio/generator-bundle": "~2.3"
},
"scripts": {
"post-root-package-install": [
"SymfonyStandard\\Composer::hookRootPackageInstall"
],
"post-install-cmd": [
"Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::removeSymfonyStandardFiles"
],
"post-update-cmd": [
"Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::removeSymfonyStandardFiles"
]
},
"config": {
"bin-dir": "bin",
"component-dir": "web/assets"
},
"extra": {
"symfony-app-dir": "app",
"symfony-web-dir": "web",
"incenteev-parameters": {
"file": "app/config/parameters.yml"
},
"branch-alias": {
"dev-master": "2.7-dev"
}
}
}
i've updated symfony/assets separately but it did not help
also tried updating sensio/framework-extra-bundle and vich/uploader-bundle
which are referencing the symfoy/asset bundle
this also did not help

Answer 1

thanks for the comments
i've installed clean symfony 2.7
based on previous composer why symfony/asset
that told me vich/uploader-bundle 1.4.2 requires symfony/asset (^2.3|^3.0)
i added it first with composer require vich/uploader-bundle
it automatically added version ^0.14.0
i've copied it to my composer and updated only it
composer update vich/uploader-bundle --with-dependencies
and after that changed symfony version to 2.7 and updated
composer update symfony/symfony --with-dependencies
everything worked fine :)