Again, there is no need to do a “hardware upgrade”. A&H has had to change internal components over time as suppliers and chip availability has changed over time. The “new” components are not better or worse, they are just different. Sometimes the firmware needs to be updated to accommodate the new components, sometimes it doesn’t.
The fact that there is no different in the user experience between any of the SQ models (old or new) should tell you how insignificant these changes have been over time.