Thank you Visvanath, I managed it finally. running 'sudo apt-get install php7.0-curl', gave nothing. Then i run
sudo apt-add-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get install php7.0-curl
did the work, now I got cURL PHP extension installed, and all checks are green, and I can continue with upgrade. Thanks.
sudo apt-add-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get install php7.0-curl
did the work, now I got cURL PHP extension installed, and all checks are green, and I can continue with upgrade. Thanks.