Using EXPCOUNTER option to create a new security file with ACID index extended to 7-bit counter.
Can this newly created security file of CA Top Secret v16 format be shared between CA Top Secret v16 and r15?
CA Top Secret r15 system needs to have RO55678 and the following PE fixes:
RO58585, RO59061, RO59783, RO60626, RO61247, RO62473, RO63350, RO63845, RO64729, RO65451, RO65717, RO63187, RO73379, and RO75732.
So all of these maintenance have been applied, you can use a new security file with ACID index extended to 7-bit counter on CA Top Secret r15 system.
Other than the above, the current CA Top Secret v16 features that would alter the security file format and, therefore, disallow sharing are: