We've replaced the metrics of the NTP diamond collector with the buit-in NTP support in prometheus-node-exporter. Support in 0.14 is pretty limited, though, it's only exporting drift and stratum. The previously used metric in the Diamond collector (delay, representing the round-trip-time to the authoratative server) is missing. We could backport https://github.com/prometheus/node_exporter/commit/c169b4b1c5108f8e56c9680e7f7b592accdc0dbd or wait until we upgrade to a more recent version of prometheus-node-exporter with that change.
Indeed, upgrading node-exporter from 0.14 to 0.16 at least would entail making some changes to e.g. command line flags and cater for the renamed metrics e.g. https://github.com/prometheus/node_exporter/blob/v0.16.0/docs/example-16-compatibility-rules.yml