1267e51b_cation_Library_for_CodeIgniter__Description
[Config Name] series [Default] usess_series [Data Type] string [Description] 
Defines an authentication token that was issued to a user who logged in using the 'Remember me' feature. This is the 'series' token referred to by Barry Jaspan.
User Login Session Configuration | User Guide | flexi auth | A User Authentication Library for CodeIgniter
Description