The previous surprise announcement was that they were going to extend the voluntary cuts to August. But the latest one here trumps that by some margin as they will be extending it to the end of next year instead. Oil has jumped on the news with WTI crude having been down 1.5% to $74.10 but is now trading positive near $76.00:
WTI crude oil
Update: The newswire that reported this news quickly withdrew the headline and the report, sending oil quickly back lower.