How to obtain or retrieve the current ITAM/ARGIS release?
To be able to determine what the current release and patch level is.

Windows

1.
You can check the following folder: C:\Program Files (x86)\CA\casm_patch_log\GOA_20180807_154626
Which holds different log files for different patches.
Asn an example it shows file T6EE399_20180807_160244.log
Which holds the following data:
Property(S): _B6B7E8AB988046BE80730C0D0D9542FB = C:\Users\ADMINI~1\AppData\Local\Temp\2\casm\Patching\GOA_20180807_154626\T6EE399_ITAM_20180807_160241\patch.msp
MSI (s) (10:54) [16:03:42:789]: Product:
CA Asset Portfolio Management - Update 'T6EE399' installed successfully.
MSI (s) (10:54) [16:03:42:790]: Windows Installer installed an update. Product Name:
CA Asset Portfolio Management. Product Version: 17.0.0.157.

And although the "Product Version: 17.0.0.157" is incorrect, it shows the applied patch:
CA Asset Portfolio Management - Update 'T6EE399' installed successfully.
And this patch 'T6EE399' is the patch included in CASM_17.1.RU1 folder structure:
\CASM-17.1.0.1-CommonPatchInstaller-Win
\CASM-17.1.0.1-CommonPatchInstaller-Win
\patches\ITAM\17_1_0_1\Binaries

2.
Possibly, other log files in this folder show other release(s) of the ITAM product as well.

3.
Another option to check for the current release is the following query on the mdb database:
SELECT installationstate,packageid,machinename,productcode,last_update_date,currentversion,previousversion
FROM al_cdb_componentinstallstate
installationstate | packageid | machinename | productcode | last_update_date | currentversion | previousversion
complete | task.itam.patch.binaries.17.1.0.1    | <machinename> | 0 | 1533638022864 | 17.1 | NULL
complete | task.itam.patch.mdb.17.1.0.1         | <machinename> | 0 | 1533638389458 | 17.1 | NULL
complete | task.itam.patch.locale.17.1.0.1      | <machinename> | 0 | 1533638402705 | 17.1 | NULL
complete | task.itam.postinstall.steps.17.1.0.1 | <machinename> | 0 | 1533638420513 | 17.1 | NULL