During the V4 upgrade, the @aave team collaborated with Sherlock in three main phases: a multi-stage collaborative audit with Blackthorn, a $365,000 audit competition, and a bug bounty program to protect the code after deployment. For one of the largest architectural changes in Aave's history, the tolerance for any overlooked issues was virtually zero. Sherlock's involvement aimed to provide in-depth research into the entirely new aspects of V4, particularly the Hub-and-Spoke architecture and the risk premium system.