Warning: Cannot modify header information

I just updated the site to version 4.5.1 and receive this on the update page:

Warning: Cannot modify header information – headers already sent by (output started at /home/xxxx/public_html/wp-admin/includes/template.php:1953) in /home/xxxx/public_html/wp-includes/pluggable.php on line 1171

I’ve read in other threads it could be a space in the PHP — checked and haven’t found one.

I’ve turned off the plug-ins – no perceived change.

I’ve tried to look for line 1953 in template.php but it only has 568 lines so I don’t know where / how the 1953 came about.

The site is yourhealingpathway.com

Thanks for any assistance you can provide.