ICANN is postponing the cryptographic key KSK Rollover as a significant number of resolvers used by ISPs and network operators are not fully ready for the change which was due on 11 October 2017.
A new date has not yet been determined, however, ICANN suggests early in 2018.
There may be multiple reasons why operators do not have the new key installed in their systems: some may not have their resolver software properly configured and a recently discovered issue in one widely used resolver program appears to not be automatically updating the key as it should, for reasons that are still being explored. ICANN Postpones KSK Cryptographic Key Rollover [icann.org]