Unable to Update to iOS 13.6.1
I plugged my iPhone 6S Plus (though for unknown reasons it still think it's a 4S) into my computer to update to iOS 13.6.1 and when I tried to update the iOS, I was informed that I need 807.5MB of free space. I have 2.16GB of available space: my iPhone says so; when I synced my phone, the sync bar said so; and the top of the Update window says so. Why can't I update my iPhone? (I have to update from my computer because if I tried to download and install on my iPhone, I will no longer have enough space to actually install the update after I download it even though I have deleted or offloaded every unneeded app.)
iPhone 6s Plus, iOS 13