Yes, that email was just about “Android OS” (how Fairphone calls its own google-certified OS) for the Fairphone 6. But Murena has already released the first Android 16 versions of /e/OS for the FP4 and FP5 yesterday, and I think the FP6 will follow soon.
Note that for a start, only the community version of /e/OS will become available for Fairphones, the official version – that everyone has who bought a Fairphone with /e/OS pre-installed – will require more time (to make sure the OTA upgrade works without problems).