The airing of last Friday's episode of Haven was delayed due to the recent tragedy in Connecticut. The season finale was originally scheduled to air this Friday, but Syfy has pushed the release to January and will air both episodes back-to-back:
"Last Friday’s 10PM episode of Haven contained scenes of fictitious violence in a high school setting and in light of the recent tragedy, we have decided to reschedule it along with the series’ season three finale, originally slated to air this Friday, December 21st at 10PM. The final two episodes of season three of Haven will now air back-to-back on Thursday, January 17th from 8-10 PM (ET/PT) to maintain the integrity of the series’ serialized nature."
The rescheduling will have no impact on the future of Haven, as Syfy recently announced the order of a 13-episode fourth season:
"Syfy has picked up drama Haven for a fourth season. Haven, based on Stephen King’s novella The Colorado Kid, has received a 13-episode order for a 2013 premiere. Haven has been a successful acquisition for Syfy as the series ranks as the No.1 cable program among Adults 18-49 and Adults 25-54 in its Friday 10-11 PM time period (in Live +7). The current third season of Haven is averaging 2.4 million total viewers and 942,000 Adults 18-49. The September 21 Season 3 premiere drew 2.8 million total viewers, a series high and up 10% from the season two premiere."