Noticed the PHP error log has been filling up with warnings (since PHP7.1)
there are various and sundry pages that pull some "legacy" library functions, among them CB's own
/subscribe-option.
Code:
[Tue Feb 13 15:20:44 2018] [warn] [client xxx.xxx.xxx.xxx] PHP Warning: A non-numeric value encountered in [redacted]/libraries/legacy/request/request.php on line 518, referer: [redacted]/en/subscribe-option
[Tue Feb 13 15:20:44 2018] [warn] [client xxx.xxx.xxx.xxx] PHP Warning: A non-numeric value encountered in [redacted]/libraries/legacy/request/request.php on line 524, referer: [redacted]/en/subscribe-option
[Tue Feb 13 15:20:44 2018] [warn] [client xxx.xxx.xxx.xxx] PHP Warning: A non-numeric value encountered in [redacted]/libraries/legacy/request/request.php on line 528, referer: [redacted]/en/subscribe-option
See the details and comments here:
github.com/joomla/joomla-cms/issues/19695#issuecomment-366019487