I just upgraded from 4.6.23 to 4.6.26. I'm on wordpress. Everything else seems to work fine. When I start a new mailing I get this error:
PHP Fatal error: Call to undefined method CRM_Mailing_BAO_Mailing: :getTemplateTypes() in ...wp-content/plugins/civicrm/civicrm/CRM/Mailing/Info.php on line 168, referer: ...
I see that getTemplateTypes is new for 4.6.26. I see in civicrm/CRM/Mailing/BAO/Mailing.php that the function is defined there.
I've commented out the reference to getTemplateTypes in civicrm/CRM/Mailing/Info.php and that allows me to start a new mailing, but now I'm getting this PHP warning:
PHP Warning: call_user_func() expects parameter 1 to be a valid c allback, class 'CRM_Mailing_BAO_Mailing' does not have a method 'getTemplateTypeNames' in .../civicrm/CRM/Core/PseudoConstant.php on line 277, ...