Yubico's YubiKey 5 series offers enhanced security features for online accounts, including cryptocurrency exchange accounts. The series supports FIDO2 and various connections, such as USB-A, USB-C, Lightning, and NFC. However, the upgrade from the legacy YubiKey 4 series may not be worthwhile unless FIDO2 support or NFC and Lightning connectivity are specifically required. The YubiKey 5 series' main advantage over the YubiKey 4 series is its FIDO2 support, which enables passwordless logins, and its NFC and/or Lightning connectivity. The two series are otherwise almost identical in terms of functionality. This highlights the importance of thoroughly assessing the need for additional security features before upgrading.