You're looking for some interesting content related to the PS Vita's 3.74 firmware and a possible link. I must clarify that I'm assuming you're referring to a hypothetical or archived link, as direct links to firmware updates or exploits are often taken down or no longer functional.
Select > Update from USB Storage Device . Key Changes in Firmware 3.74 ps vita 374 firmware link
Before you hit that update button, you must ask yourself: You're looking for some interesting content related to