It shouldn't be an issue. Those warnings and errors, are for files that belong to a library that adds PHP 7 functions to earlier versions of PHP for back compatibility. https://github.com/paragonie/random_compat/tree/master/lib
Functions like randombytes_, available since PHP 7. http://php.net/random_bytes
So if your PHP installation has the function, i.e. PHP 7+, the files with the code that would give an error, would not be loaded. E.g. from s2member/src/vendor/paragonie/randomcompat/lib/random.php_
* We only want to use mcypt_create_iv() if:
* - random_bytes() hasn't already been defined
* - the mcrypt extensions is loaded
* - One of these two conditions is true:
* - We're on Windows (DIRECTORY_SEPARATOR !== '/')
* - We're not on Windows and /dev/urandom is readabale
* (i.e. we're not in a chroot jail)
* - Special case:
* - If we're not on Windows, but the PHP version is between
* 5.6.10 and 5.6.12, we don't want to use mcrypt. It will
* hang indefinitely. This is bad.
* - If we're on Windows, we want to use PHP >= 5.3.7 or else
* we get insufficient entropy errors.
// Windows on PHP < 5.3.7 is broken, but non-Windows is not known to be.
(DIRECTORY_SEPARATOR === '/' || PHP_VERSION_ID >= 50307)
// Prevent this code from hanging indefinitely on non-Windows;
// see https://bugs.php.net/bug.php?id=69833
DIRECTORY_SEPARATOR !== '/' ||
(PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
// See random_bytes_mcrypt.php
require_once $RandomCompatDIR . '/random_bytes_mcrypt.php';
$RandomCompatUrandom = null;
Feel free to test in a dev installation before upgrading the live site to PHP 7.2 if you feel insecure, though. And it's always good practice to create a full backup before such a change.
I hope that helps!