Honestly doesn't matter but
"NOTE: The new amp algorithms are more accurate than prior firmware releases. This creates various “artifacts” that real tube amps produce. These include low-frequency intermodulation distortion, “clutter”, spitting and other non-ideal behaviors. These behaviors, however, are precisely what gives tube amps warmth, dynamics and character. They go hand-in-hand. Without these, amp modeling sounds sterile and uninteresting."
New amp algo for this firmware is being touted as more accurate and the calling card to this accuracy seems to be these "artifacts". Cliff then goes on to say without said artifacts modeling sounds sterile and uninteresting. So if these "artifacts" weren't in the previous firmwares, which it appears they were not, then previous firmwares amp modeling was sterile and uninteresting (to cliff)