This document seems to indicate that a hardlink can be used to keep the ese.dll and eseutil.exe files consistent: https://docs.microsoft.com/en-us/system-center/dpm/back-up-exchange?view=sc-dpm-1801.
However, doesn't ese.dll and eseutil.exe need to be copied to the bin folder on the DPM server from the Exchange server? If that is the case, how can a hardlink be used? The article seems to imply the copy is in the DPM agent folder on the protected Exchange server, not the bin folder of DPM.