Input required for upgrading identityIQ from 8.3p4 to 8.4p3

also here you can find the well documented steps :

IIQ Upgrade from 8.3 to 8.4 - IdentityIQ (IIQ) / IIQ Discussion and Questions - SailPoint Developer Community

also this doc is more useful for me all time when i do upgrade

IdentityIQ Upgrade Plan document template - Compass

pls let us know if you able to fix the problem.