IF you update to the latest security patch of July you cannot downgrade your software again on your device.
This is because with the July update, Samsung has updated the fuse versions of Knox. It's a part of Knox's "RP" which stands for "Rollback Prevention".
The RP fuse version number is set when system software is initially installed and when specific updates occur. Once the RP fuse version number is set, it is impossible to revert back to legacy software versions.
