Publishing Assistant 6 is fully tested and supported for InDesign version CS6, CC, CC 2014, 2015, 2017, 2018, 2019 and 2020.
Theoretically Publishing Assistant also can work with earlier versions of InDesign (CS2, CS3, CS4, CS5, and CS5.5). However, only limited ongoing testing can be been performed on these versions. And only limited support is available for InDesign versions prior to CS6.