PHP 7.1 warnings

On a server recently upgraded to the now released PHP 7.1:

OSSEC HIDS Notification.
2016 Dec 05 08:26:35

Received From: cumberland->/var/log/httpd/www.sterndata.com-error_log
Rule: 1002 fired (level 2) -> "Unknown problem somewhere in the system."
Portion of the log(s):

[Mon Dec 05 08:26:35.727222 2016] [php7:warn] [pid 29198] [client 104.131.221.131:51674] PHP Warning:  Illegal string offset 'run' in /var/www/www.sterndata.com/wordpress/wp-content/plugins/backwpup/inc/class-cron.php on line 133, referer: https://www.sterndata.com/wp-cron.php?_nonce=d5bfaba7b4&doing_wp_cron=1480947995.1826128959655761718750&backwpup_run=runnow&jobid=1

 --END OF NOTIFICATION

OSSEC HIDS Notification.
2016 Dec 05 08:26:35

Received From: cumberland->/var/log/httpd/www.sterndata.com-error_log
Rule: 1002 fired (level 2) -> "Unknown problem somewhere in the system."
Portion of the log(s):

[Mon Dec 05 08:26:35.727287 2016] [php7:warn] [pid 29198] [client 104.131.221.131:51674] PHP Warning:  Illegal string offset 'nonce' in /var/www/www.sterndata.com/wordpress/wp-content/plugins/backwpup/inc/class-cron.php on line 137, referer: https://www.sterndata.com/wp-cron.php?_nonce=d5bfaba7b4&doing_wp_cron=1480947995.1826128959655761718750&backwpup_run=runnow&jobid=1

 --END OF NOTIFICATION

OSSEC HIDS Notification.
2016 Dec 05 08:26:35

Received From: cumberland->/var/log/httpd/www.sterndata.com-error_log
Rule: 1002 fired (level 2) -> "Unknown problem somewhere in the system."
Portion of the log(s):

[Mon Dec 05 08:26:35.727326 2016] [php7:warn] [pid 29198] [client 104.131.221.131:51674] PHP Warning:  Illegal string offset 'jobid' in /var/www/www.sterndata.com/wordpress/wp-content/plugins/backwpup/inc/class-cron.php on line 141, referer: https://www.sterndata.com/wp-cron.php?_nonce=d5bfaba7b4&doing_wp_cron=1480947995.1826128959655761718750&backwpup_run=runnow&jobid=1

 --END OF NOTIFICATION