If you've been captivated by Blue Planet II recently, good news: the original Blue Planet will soon be on iPlayer, in addition to Planet Earth, Frozen Planet and last year's Planet Earth II. The BBC has experimented with digital box sets before — back in 2014, for instance, it dropped the full series of Jonah from Tonga at once. It's unusual, however, for the BBC to bring back old programming. Beyond the new BBC archive, most shows disappear after 30 days. Today's announcement is a Christmas special — the shows will disappear again in the New Year — but maybe, just maybe, it's a precursor to a larger, permanent shift in the BBC's iPlayer strategy.