Just another hypothesis that came to my mind is that it could be only a placeholder to a new special. MPT put Celtic Woman The Best Of around the same date, I think they will change that in the next weeks as an official announcement is dropped.
I think it's unlikely, though; The first post of this topic has the mention "Postcards From Ireland" on it...
I wonder if we’re headed for a repeat of the Destiny/VoA/Homecoming era.
When I say that it’s because
August ‘15: Destiny recorded.
November ‘15: Destiny began airing.
January ‘16: Destiny CD/dvd/Blu-ray released.
February ‘16: Destiny world tour began.
August ‘16: Voices of angels recorded.
October ‘16: Destiny world tour finished — Destiny fulfilled.
November ‘16: Voices of Angels released.
Holidays ‘16: Destiny reairing — a Wednesday night airing here had a live pledge event where you could call and get M&G tickets/the CD of Destiny (I ended up getting VoA at target).
March ‘17: VoA tour
September ‘17: Homecoming recorded.
Holidays ‘17: Homecoming aired (I caught a 9p airing four days after thanksgiving).
February ‘18: End of VoA tour.
So I wonder if…..
Postcards from Ireland filmed released and aired — check. I DVrd a Friday night airing and watched it.
Postcards from Ireland tour is over as of the Ireland shows.
New album with new arrangements of old songs (especially the original show, A New Journey, Believe and Destiny)/a few new ones). One that is a lot similar to VoA — new member (Tara) introduced on VoA and there’s a new member now. Only an album and no DVD/special.
Postcards from Ireland reairing a La the holiday ‘16 reairing of Destiny??
New tour.
Show recorded later (something similar to either Emerald/Homecoming) and then released as live disc (like Homecoming) + aired on PBS.