Upgrading arch question

Is it possible to upgrade arch from 2016.10.01 version install to the latest version of 02/202. Im on a older 2010 dell inspirion desktop and I must install in legacy bios mode which is fine but will the new upgrade work with legacy. Im downloading the old version now because when I followed your old video for 2016.10.01 iso with the brand new iso from 02/2021 it broke where I was updating mkinitcpio -p linux tell me file doesnt exit. I installed linux-headers and linux-lts and linux-lts-headers. I then correctly edited /etc/mkinitcpio.conf and added encrypt lvm2 right where you state to than ran mkinitcpio -p linuxand it failed telling me there was no file. I discovered it only had a file for th lts version of kernel so my thought is this: install the actual version from you old video and then do a full upgrade. Any thoughts and do you think this will work?
thank you for any input

I really wish I could give you a vote of confidence, but an installation from that long ago will likely have multiple manual-interventions needed in order to bring it current. I recommend backing it up (take an image) and then you can try and see if you can, but I think it will be less time-consuming to do a new install at this point.