Laravel Project Version Downgrade

If your server doesn't have php 7.1 and above and you are only restricted to use php7.0 do as below:

1. Delete vendor folder
2. Delete composer.lock file
3. Add this to composer.json file under config
   

   "platform": {
      "php": "7.0.0"
   }

As well, ensure PHP version under require is set to 7.0.0 as shown below in config.platform.php:

    "config": {
        "platform": {
            "php": "7.0.0"
        }
     }

4. Run composer install using CMD

5. composer install --ignore-platform-reqs 

   if you get the error: 
   This package requires php >=5.5.9 but your PHP version (5.5.6)
      does not satisfy that requirement.

    

This now will make sure that only dependencies compatible with php7.0 are installed