function_usable error message in EE 2.6.0

Hi guys,

I think I’ve found a bug in the EE 2.6.0 release. I’m setting up a new site with this release and I have my email settings configured to use Sendmail. I installed the Stash module, v2.3.6, which suggests that you modify the webroot index.php file (see Stash docs). After doing this i can no longer load any CP page. All I get is the following error:

Fatal error: Call to undefined function function_usable() in /home/…/system/codeigniter/system/libraries/Email.php on line 1761

Of course, I know that pre-EE2.6.0 whenever you modified the webroot index.php file, EE would ask you to accept the changes made to the file. I assume now that it is attempting to send off an email notification. I believe that when it attempts to send off the email via sendmail this error is being encountered.

Can EE’s dev team confirm if this is in fact a bug with the 2.6.0 release?