Thanks Stuart,
Comparing things to what happened when version 17 went GA, this makes sense.
I believe that it is only the first incremental release of version 18 (INC00) which has been published GA. The EOS date for version 16 was only announced when the final incremental release for version 17 was published as GA. If similar timescales are followed, it could be the end of this year before we could expect an EOS for version 17 to be announced.