Error during installation

[JayRhithu]

OS: Ubuntu 18.04

While running 'composer install' I am getting these errors:

  - Installing classpreloader/classpreloader (1.0.2): Downloading (100%)         
  - Installing laravel/framework (v4.2.22): Downloading (100%)         
symfony/translation suggests installing symfony/config
symfony/translation suggests installing symfony/yaml
paragonie/random_compat suggests installing ext-libsodium (Provides a modern crypto API that can be used to generate random bytes.)
symfony/security-core suggests installing symfony/expression-language (For using the expression voter)
symfony/security-core suggests installing symfony/validator (For using the user password constraint)
symfony/routing suggests installing doctrine/annotations (For using the annotation loader)
symfony/routing suggests installing symfony/config (For using the all-in-one router or any loader)
symfony/routing suggests installing symfony/expression-language (For using expression matching)
symfony/routing suggests installing symfony/yaml (For using the YAML loader)
symfony/event-dispatcher suggests installing symfony/dependency-injection
symfony/http-kernel suggests installing symfony/class-loader
symfony/http-kernel suggests installing symfony/config
symfony/http-kernel suggests installing symfony/dependency-injection
symfony/http-kernel suggests installing symfony/var-dumper
predis/predis suggests installing ext-phpiredis (Allows faster serialization and deserialization of the Redis protocol)
phpseclib/phpseclib suggests installing ext-mcrypt (Install the Mcrypt extension in order to speed up a wide variety of cryptographic operations.)
phpseclib/phpseclib suggests installing pear-pear/PHP_Compat (Install PHP_Compat to get phpseclib working on PHP < 4.3.3.)
patchwork/utf8 suggests installing ext-wfio (Use WFIO for UTF-8 filesystem access on Windows)
monolog/monolog suggests installing aws/aws-sdk-php (Allow sending log messages to AWS services like DynamoDB)
monolog/monolog suggests installing doctrine/couchdb (Allow sending log messages to a CouchDB server)
monolog/monolog suggests installing ext-amqp (Allow sending log messages to an AMQP server (1.0+ required))
monolog/monolog suggests installing ext-mongo (Allow sending log messages to a MongoDB server)
monolog/monolog suggests installing graylog2/gelf-php (Allow sending log messages to a GrayLog2 server)
monolog/monolog suggests installing mongodb/mongodb (Allow sending log messages to a MongoDB server via PHP Driver)
monolog/monolog suggests installing php-amqplib/php-amqplib (Allow sending log messages to an AMQP server using php-amqplib)
monolog/monolog suggests installing php-console/php-console (Allow sending log messages to Google Chrome)
monolog/monolog suggests installing rollbar/rollbar (Allow sending log messages to Rollbar)
monolog/monolog suggests installing ruflin/elastica (Allow sending log messages to an Elastic Search server)
monolog/monolog suggests installing sentry/sentry (Allow sending log messages to a Sentry server)
laravel/framework suggests installing doctrine/dbal (Allow renaming columns and dropping SQLite columns.)
Generating autoload files
> php artisan clear-compiled
Mcrypt PHP extension required.
Script php artisan clear-compiled handling the post-install-cmd event returned with error code 1

I already installed php5.6 and php5.6-mcrypt

Please help

[henok-tesfu]

Your PHP version should be higher PHP >= 7.2.5 the project is running on "laravel/framework": "6.20.*" for more check this link https://laravel.com/docs/6.x/installation#server-requirements