The Callback Campaign is scheduled to end on Tuesday, July 18th following the maintenance for patch 4.05.

If your friends are taking a break, don't miss this chance to invite them back for fantastic new adventures in Stormblood, and earn special rewards if you meet the campaign requirements!
* Friends can be invited to return via the friends list in-game until Tuesday, July 18. Players invited to return must do so within 30 days of the campaign's end to receive rewards.

Read on for more details.