Unable to update a laravel project from 5.5 to 5.7 - php

Question

I recently started working on a project that was originally in Laravel 5.2 which I successfully upgraded to Laravel 5.5 however now I'm trying to upgrade once again to Laravel 5.7 but when I do a composer update it gets stuck at Resolving dependencies through SAT. Here is the required and required-dev section of composer.json file:
"require": {
"php": "^7.2.0",
"laravel/framework": "5.7.*",
"laravel/tinker": "~1.0",
"laravelcollective/html": "^5.5.0",
"unisharp/laravel-ckeditor": "^4.5",
"barryvdh/laravel-debugbar": "^3.1",
"milon/barcode": "^5.2",
"barryvdh/laravel-dompdf": "^0.8.0",
"hisorange/browser-detect": "2.*",
"sentry/sentry-laravel": "^0.7.0",
"laravel/cashier": "~6.0",
"dingo/api": "1.0.*#dev"
},
"require-dev": {
"fzaninotto/faker": "^1.4",
"mockery/mockery": "^1.0",
"phpunit/phpunit": "^7.0",
"symfony/css-selector": "2.8.*|3.0.*",
"symfony/dom-crawler": "2.8.*|3.0.*",
"xethron/migrations-generator": "dev-l5",
"way/generators": "dev-feature/laravel-five-stable"
},
Not sure what could be the problem.... Is there something missing?

Answer 1

The issue is likely to do with one of the pages you're trying to install / update. If composer install -vvv doesn't give you any information on what package might be causing the error, you'll need to troubleshoot by trying to install each package individually using:
composer require unisharp/laravel-ckeditor:4.5
composer require barryvdh/laravel-debugbar:3.1
...
Eventually, composer will tell you which package is causing the issue. Once you identify the packages, you'll need to check that the version you're trying to install is compatible with Laravel 5.7. Tweak the version number in the composer require ... command line until you find one that works (could be higher or lower).