Although, the official concept haven't been decided. OSEN had directly communicate to SM Entertainment and neglected all the rumours of their comeback manly concept.
According to all of the passing rumours, not long ago, Girls' Generation picked an official concept for their album and actually started the filming of their Music Video from 6th December. From now, it can be certainly confirmed that their comeback time will be on January next year. The details be stated that they will try a completely new manly concept, however it hasn't been confirmed officially from the SM Entertainment

On the 7th December, OSEN had a direct call to the SM Entertainment for confirmations. One of the representative informed: "Girls' Generation is currently preparing for a next year comeback. There haven't any exact schedule, however, we are planning and will inform publicly as soon as possible." The representative also be asked about their newest comeback concept, the representative stated: "It won't be a manly concept, but you will still be able to anticipate in their new concept and appearance."

Source: OSEN, Hankooki
Translation and written: totoropie @TheSoneSource