Proposal

Following the DevSummit consensus we decided to rename CT feature to ST (StartTimestamp) for consistency with the wider ecosystem, planned storage changes (PROM-60) and the potential delta temporality (PROM-48)

This issue tracks the renaming work:

• Remote Write 2.0 (not yet stable, so we can change it) (impl, spec)
• Prometheus codebase (feat: rename CreatedTimestamp to StartTimestamp #17523)
• Prometheus/docs
• PrometheusProto (changing name is non breaking in proto)
• OpenMetrics 2.0 (PR)
• Native histogram spec (https://prometheus.io/docs/specs/native_histograms/) cc @krajorama @beorn7
• Prometheus SDKs (at least add issue for clients, unlikely we can change some APIs now)

Things that explicitly stay with old naming "created timestamp":

• OpenMetrics 1.0 (will be replaced by 2.0)
• created-timestamp-zero-ingestion feature flag (will be deprecated eventually).