Multiple SERP trackers picked up high flux around March 18-19, with MozCast peaking at 101.1°F on March 18th. No update was officially confirmed, and Danny Sullivan of Google tweeted that "I did check, no one knows of any broad, major update."
Google confirmed a significant product reviews update and changed the naming convention to match the Core Updates. The update officially took 19 days to roll out, starting on March 23rd, and built on previous product review updates to identify high-quality product reviews.
On May 25th, Google announced the rollout of a core update. The rollout lasted roughly 2 weeks and was completed on June 9th. MozCast recorded peak ranking flux at 103.0°F on May 25th, the first day of the rollout. As with most Core Updates, Google did not provide specifics.