I was do setup the magento 2.3.4 version in Php 7.3 version
But Frontend throw error
Fatal error: Composer detected issues in your platform: Your Composer dependencies require a PHP version ">= 7.4.0". You are running 7.3.33-1+ubuntu20.04.1+deb.sury.org+1. in /magentoroot/vendor/composer/platform_check.php on line 24
After i runed below commands :
composer install, composer update and composer -v
it is thow error
Fatal error: Uncaught Error: Call to undefined function Composer\Json\json_decode() in /usr/share/php/Composer/Json/JsonFile.php:169
How to solve this problem ?