After upgrading php from 5.2 to 7.2 , while checking out on woocomeerce getting internal server error, when i check the error log in woocommerce it gives the following.
CRITICAL Uncaught ArgumentCountError: Too few arguments to function iwc_display_payment_method_email_order(), 1 passed in /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-includes/class-wp-hook.php on line 288 and exactly 2 expected in /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-content/themes/lensa/functions.php:133
Stack trace:
#0 /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-includes/class-wp-hook.php(288): iwc_display_payment_method_email_order(Object(WC_Order))
#1 /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#2 /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#3 /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-content/themes/lensa/woocommerce/emails/email-order-details.php(89): do_action('woocommerce_ema...', Object(WC_Order), true, false, Object(WC_Email_New_Order))
#4 /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-content/plugins/woocomm in /home/content/n3pnexwpnas04_data01/18/41356818/html/wp-content/themes/lensa/functions.php on line 133
You can't easily update your Wordpress in such a way. You have to update your Software and all of the dependencies and make them PHP 7.2 compatible. So before your switch to the newest version update your Wordpress and all Plugins.
Then you can switch your PHP-Version and try to fix all other problems. I think in your case with such a big step forward. You should install a new Wordpress and try to migrate all the plugins step by step and fix the problems.