I have tried to run an existing laravel project. But during composer update I got this error:

Problem 1

- Root composer.json requires gabrielbull/ups-api ^0.8.0 -> satisfiable by gabrielbull/ups-api[0.8.0].
- gabrielbull/ups-api 0.8.0 requires php ^5.5 || ^7.0 -> your php version (8.0.0) does not satisfy that requirement.

Problem 2

- Root composer.json requires mehedi-iitdu/laravel-paystack dev-master -> satisfiable by mehedi-iitdu/laravel-paystack[dev-master].
    - mehedi-iitdu/laravel-paystack dev-master requires php ^7.0 -> your php version (8.0.0) does not satisfy that requirement.

Problem 3

- laravel/framework[v5.8.0, ..., 5.8.x-dev] require php ^7.1.3 -> your php version (8.0.0) does not satisfy that requirement.
- Root composer.json requires laravel/framework 5.8.* -> satisfiable by laravel/framework[v5.8.0, ..., 5.8.x-dev].

Answer

The error messages are quite clear. The packages you want to install require PHP 7, but you have PHP 8 installed.

Your options are:

• Downgrade your PHP version
• Upgrade the package versions you depend on, if there are newer PHP 8 compatible versions