I upgraded MW to 1.26.2, and I also updated the LDAPAuthentication extension to the latest version. The domains no longer show up in the dropdown box on the Login page. The dropdown box is now empty. Logins are not working anymore.
Topic on Project:Support desk
I solved the issue. I don't think it is MW version related. The update for the LDAPAuthentication extension changed the order in which you can place the config options in LocalSettings.php. You must specify the following options first before any other options:
require_once('extensions/LdapAuthentication/LdapAuthentication.php');
$wgAuth = new LdapAuthenticationPlugin();
In an older version of the extension, it was perfectly valid to specify these items last. That was useful because I have many separate wiki instances sharing the same MW code base, and I always put these lines in each wiki's custom LocalSettings file. Then, if for some reason I wanted to disable LDAP for a particular wiki, I would just comment out these lines for that wiki. The other wiki instances would continue to use LDAP. I have the domains and the other LDAP options in a global LocalSettings file so that every wiki instance gets the same LDAP domains and settings.