Just in case this helps with that future release:
I just had ANOTHER site with old content start to produce PHP errors on the home page.
jondavisjr.com
Here is the error message:
src
Warning: Cannot modify header information – headers already sent by (output started at /home/**SECRET**/public_html/domains/jondavisjr.com/wp-content/plugins/vipers-video-quicktags-migrator/vipers-video-quicktags-migrator.php:1) in /home/**SECRET**/public_html/domains/jondavisjr.com/wp-content/plugins/sg-cachepress/core/Supercacher/Supercacher_Helper.php on line 41
I don’t have the skill level to interpret that, but I can see the names of vipers video quicktags migrator and my sg-cachepress plugin (which is a plugin provided by my hosting company).
Yesterday I was unable to view my site or login at all until I accessed the site via ftp and changed the name of the vipers quicktag plugin thus deactivating it.
When I changed the name back and reactivated vipers quicktag again in the wordpress dashboard I got this message on my wordpress dashboard:
“The plugin generated 4 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.”
I’m not sure if this is related to the same problem or not, but it is curious that it is happening about the same time as the problems on my freedomthirst.com site.
I am deactivating the vipers video quicktags migrator plugin for now.
Let me know if turning it back on will help you out in any way – but it does make my site show php errors, and in some cases ONLY php errors.