• [CHANGE] Extend sharding capabilities to additionalScrapeConfigs. #4324
• [CHANGE] Remove app label from Prometheus, Alertmanager and Thanos Ruler statefulsets/pods. #4350
• [FEATURE] Add alertRelabelConfigs field to the Thanos Ruler CRD for configuring Prometheus alert relabeling features. #4303
• [FEATURE] Add support for updated matching syntax in Alertmanager's raw config for inhibit_rules and route. #4307, #4309
• [FEATURE] Add validating webhook for AlertManagerConfig. #4338
• [FEATURE] Adds support for Sigv4 when configuring RemoteWrite. #3994
• [ENHANCEMENT] Add "generic ephemeral storage" as a data storage option for Alertmanager, Prometheus and Thanos Ruler. #4326
• [ENHANCEMENT] Improve docs and error message for "smarthost" field. #4299
• [ENHANCEMENT] Add alerts for config reloader sidecars. #4294
• [ENHANCEMENT] Add validations for duration and size fields for Prometheus, Alertmanager, and Thanos Ruler resources #4308, #4352
• [ENHANCEMENT] Add s390x support to docker images. #4351
• [ENHANCEMENT] Only load alertmanager configuration when writing configration. #4333
• [BUGFIX] Fix matchLabels selector to have empty label values in ServiceMonitor, PodMonitor, and Probe. #4327
• [BUGFIX] Prevent rule file name collision. #4347
• [BUGFIX] Update native kubernetes fields used in prometheus-operator CRDs. #4221