Problem of Laravel Framework version for using the package mailjet/laravel-mailjet

Question

I've a problem for using mailjet/laravel-mailjet, it seems a problem of versions. I was using Laravel Framework 5.6.33 and i got

Can only install one of: laravel/framework[v5.6.39, 5.4.x-dev].

i've change my composer.json and now, i'm using Laravel Framework 5.6.39 but i've still the same problem

 $ php artisan --version
Laravel Framework 5.6.39

There is the answer when i try to install mailjet/laravel-mailjet

$ composer require mailjet/laravel-mailjet
Using version ^1.1 for mailjet/laravel-mailjet
./composer.json has been updated
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
    - Can only install one of: laravel/framework[v5.6.39, 5.4.x-dev].
    - Can only install one of: laravel/framework[5.4.x-dev, v5.6.39].
    - Can only install one of: laravel/framework[5.4.x-dev, v5.6.39].
    - mailjet/laravel-mailjet 1.1.0 requires laravel/framework 5.4.* -> satisfiable by laravel/framework[5.4.x-dev].
    - Installation request for mailjet/laravel-mailjet ^1.1 -> satisfiable by mailjet/laravel-mailjet[1.1.0].
    - Installation request for laravel/framework 5.6.39 -> satisfiable by laravel/framework[v5.6.39].

Answer 1

the 4th line explains it all.

mailjet/laravel-mailjet 1.1.0 requires laravel/framework 5.4.*

so, you can't use v5.6.39, only 5.4.*