Why hasn't the CALDBVER keyword been updated after I run this tool?
If you would like to manually change the value, e.g. to recall later what version was used in reprocessing the data, use dmhedit:
unix% dmhedit infile="acis_new_evt2.fits" filelist="" operation="add" \ key="CALDBVER" value="22.214.171.124" datatype="indef" unit="" comment="CALDB version"
The Note on Processing Versions shows how to determine what version of the CALDB is installed on your system.