Kindly refer to the documents which portrays exactly the difference between the Arm architecture Armv7 to Armv8.
At least the overview of the changes in terms of advantages and disadvantages
The ARMv8 instruction set is divided into the Aarch64 and Aarch32 instruction sets, while the ARMv7 uses the A32 and T16 instruction sets (32-bit and 16-bit, respectively peryourhealth).