Occasionally, Y2R strategists will come out with a new innovative strategy, or yield farms change their reward contracts. If that's the case, Y2R vaults have the flexibility to adapt to these changes, and have the ability to swap strategies so users don't have to migrate their funds to a new vault: it's done automatically by a strategy upgrade.
The new strategy is deployed with a dummy vault and all of the manual tests outlined above are completed. After passing the checks, the new strategy is assigned to the vault. The vault gets proposed the new strategy through a multi-sig wallet and has to wait until the timelock delay has passed before the vault uses the new strategy.
Sometimes something can go wrong with the underlying yield farm, and reacting quickly is of great importance. Y2R strategies have a keeper that is allowed to panic, which withdraws the staked funds from the farm back to the strategy contract and removes all allowances. This ensures that funds are always available for Y2R stakers to withdraw in case of emergency.