mcrypt_get_iv_size() is deprecated

[azimidev]

I get this after installation and running the sever
mcrypt_get_iv_size() is deprecated

[ngangavic]

In your config/app.php configuration file, you should update the cipher to "AES-256-CBC" and set your key to a random 32 byte string which may be securely generated using php artisan key:generate
Check this