When a GA version of CA Service Desk Manager (CA SDM) is installed in an upgraded environment, any existing patch history file that may exist is not retained or automatically archived.
The patch history file would get created as soon as the first CA SDM patch is applied to the upgraded environment.
Therefore, the patch history file that exists only applies to the current version of CA SDM that is installed in the environment.
Please follow the best practices of backing up the environment before an upgrade, and testing the upgrade in a non-production/test environment. The patch history file (and other files such as the NX.env file) from the pre-upgrade environment would then be available from the backup/restore, archive, and/or snapshot.