I successfully upgraded to 2.7 on one site but then on my other site I get this error:
Warning: Cannot modify header information - headers already sent by (output started at /home/content/g/e/n/gendress/html/wp-content/themes/notepad.1.1.1/notepad/functions.php:19) in /home/content/g/e/n/gendress/html/wp-includes/pluggable.php on line 850
There seems to be an issue directly related to the theme I am using and I don't know how to switch out the themes on the back-end or how to fix the conflict in the code.