May 24, 2018. Difficulty rose by +3.94% to 4.31T from 4.14T.
Change
+3.94%
New difficulty
4.31T
Period length
13.5 days
Network hashrate then (7-day)
30.8 EH/s
Bitcoin price then
$7,512
Hashprice then
$487/PH/day
The 2,016 blocks before it took 13.5 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 3.94%: an ordinary adjustment. For every machine on the network that is a pay cut of the same size until the next retarget.