No expert on this but I believe that will be the case. My Ipod has a much earlier version and tells me it is up to date and I have an old iphone that also has quite an old version and tells me that it is up to date.
I think Apple might want you to buy a new Ipad
I have also noticed that my Iphone SE seems to run it’s battery down quicker after every update
I have the same problem with my battery.
Does anyone know if a new battery will fix this or do i have to buy a new phone?