If the UI components used in application are already complaint with Pega version 7.19, then we do not need to run the upgrade utilities.
However the following things are recommended.
Update Existing Applications, Final Conflicts.
Upgrade Data Tables is required, if the new columns/indexes introduced in the Pega 7.4 version needs to be utilized. Only the OOTB tables such as pc_work, pc_history and pr_history would get updated, the application specific work,history tables changes has to be performed manually after verifying the changes in the lower environment.