does a periodic boundary condition for u implement inflow u (boundary1) = outflow u (boundary2) in newer comsol versions as well? (periodic boundary condition for the flux)

Dear everyone,

I have a question about the implementation of periodic boundary conditions for fluxes, so that the inflow through one boundary equals the outflow through the other. In comsol 3.5, this condition was 'automatically' implemented when chosing periodic boundary conditions for a dependent variable with Neumann boundary conditions (no flux). Is this the same in the newer versions? (And if not, how can i implement this instead? I am working with the matlab live link, but any hint is highly appreciated) I cannot find any information about this neither in the manuals nor in internet ressources, so if you know the answer, PLEASE let me know, it won't take you ong to write a line, but help me a lot :)

All best,
Sabine