The remote Oracle client should be the same 188.8.131.52 32-bit client you install when pointing to any remote server for BSI, rather than the 12cR2 release - we rely on the library versions matching when making calls to them. The 11.2 client can still speak to a 12c server.
ODAC112040Xcopy_32bit is the exact version string you're after.
Please note that the Oracle "Instant Client" does not make the relevant Registry entries that we require to see it in the installer, nor does it configure PATH, ORACLE_HOME and TNS_ADMIN environment variables - you will need to do this.
Create the top level Oracle registry key:
In the above, create a sub-key starts with "KEY_" followed by the name of the installation you want, e.g.:
Now create three string values in that key:
NLS_LANG = AMERICAN_AMERICA.WE8MSWIN1252 (this is an example; you will need to select the same as the database server)
ORACLE_HOME = c:\app\oracle\client\instantclient (the folder you installed it to)
ORACLE_HOME_NAME = INSTANT (choose a name to match the one above)
The installer can now find the client and the install should progress.
Please note: With the latest cumulative patches on 8.3.5 we now support the Oracle 12 (32-bit) client as well. Please note that the ODAC should match the client version you use. If you want to upgrade the client on an existing APP/WEB you would just backup your tnsnames.ora, uninstall the old client, install the new one, and replace tnsnames.ora.