Publishing Assistant is fully tested and supported for InDesign version CS6, CC, CC 2014, CC 2015, CC 2017, CC 2018 and CC 2019.
Theoretically Publishing Assistant also can work with InDesign CS, CS2, CS3, CS4, CS5, and CS5.5. However, only limited testing has been performed on these versions. And only limited support is available for InDesign versions prior to ID CS 6.
In terms of typesetting features PA 5.1 and PA 6.0 are identical.
The major difference is that PA 5.1 work only with Paratext 7 translation projects and does not work with Paratext 8 projects. Conversely, PA 6 works only with PT 8 project and is useless for PT 7 projects. Please keep also in mind that PA 6 requires separate registration.
Yes and no.
Yes, you can use Publishing Assistant on Apple Mac computers with Windows (64-bit version) running.
No, you can not use PA with MacOS.