There are several ways to identify your Oracle Instant Client Version.
A. from SM51->”Release Notes”
1. Go to SM51 -> Release Notes
2. You can read the current Oracle Instant Client Version
B. Windows: from oraocci<version>.dll
1. Go to folder DIR_EXECUTABLE in this example is E:\usr\sap\SOL\SYS\exe\uc\NTAMD64. Right click file oraocci10.dll -> Details