0.34.0 / 2026-08-16

• [CHANGE] notify: The reason label on alertmanager_notifications_failed_total now distinguishes authError (HTTP 401/403) and rateLimited (HTTP 429) from the generic clientError. Dashboards/alerts matching reason="clientError" for these codes must be updated. #5332
• [FEATURE] Add optional templatable labels to alert routes. #5328
• [FEATURE] eventrecorder: Add inhibit rule names to inhibition_muted_alert events. #5315
• [FEATURE] eventrecorder: Add stdout output type. #5311
• [FEATURE] silences: Add active, expired, and pending boolean filter parameters to GET /api/v2/silences to allow filtering silences by state server-side. #5406
• [FEATURE] sns: Add aws external_id support in sigv4 configuration. #5157
• [FEATURE] template: Add toDate and mustToDate functions. #5327
• [ENHANCEMENT] doc: Add AlertmanagerClusterFailedPeers alertmanager-mixin. #5301
• [ENHANCEMENT] doc: Add description for Rocketchat parameters in global config. #5181
• [ENHANCEMENT] doc: Add top level tracing configuration key. #5314
• [ENHANCEMENT] doc: Fix Alertmanager port in amtool config routes example. #5312
• [ENHANCEMENT] eventrecorder: Add optional webhook batching. #5392
• [ENHANCEMENT] notify: The discord and webex integrations now report a failure reason on alertmanager_notifications_failed_total. #5332
• [ENHANCEMENT] ui: Improve responsiveness of UI when loading thousands of alerts. #5357
• [BUGFIX] eventrecorder: Fixed a minor performance regression when the event recorder is enabled. #5307
• [BUGFIX] msteamsv2: Inherit global proxy_url into partial http_config. #5379
• [BUGFIX] webhook: Keep custom payload string values verbatim instead of reinterpreting JSON leaves that look like YAML (e.g. values ending with a colon). #5304

0.33.1 / 2026-07-04

• [BUGFIX] doc: fix missing notification_reason field in webhook documentation (#5329)
• [BUGFIX] silences: fix silences snapshot missing legacy matchers field. This caused a bug that prevented older alertmanager versions from reading newer snapshots unnecessarily. (#5330)
• [BUGFIX] silence with no matchers should populate an empty array in API response (#5331)

0.33.0 / 2026-06-12

• [CHANGE] The '--enable-feature=auto-gomaxprocs' option has been removed. This flag had no effect since v0.29 and was deprecated in v0.32. It can be safely removed from any startup scripts. #5090, #5251
• [CHANGE] Add group-key-in-metrics feature flag. #5047
• [CHANGE] Move AlertMarker, GroupMarker to marker package. #5047
• [CHANGE] Remove alertmanager_marked_alerts. #5047
• [CHANGE] Remove the following from types package: MemMarker, AlertState*, AlertStatus. #5047
• [FEATURE] Introduce per aggregation group AlertMarkers and drop Global Alert Marker. #5047
• [FEATURE] ui: Add support for silence annotations. #5017
• [FEATURE] api: Add receiver labels and receiver_matchers filter to /api/v2/receivers, /api/v2/alerts, and /api/v2/alerts/groups. #5152
• [FEATURE] eventrecorder: Add structured event recorder behind --enable-feature=event-recorder, with file, webhook, and kafka outputs. #5072, #5246
• [ENHANCEMENT] Add the use_aws_http_client config option to the sns notifier. #5178
• [ENHANCEMENT] template: Add now function to get current time. #5188
• [ENHANCEMENT] docs: Clarify YAML quoting vs matcher token quoting in UTF-8 matchers section. #5264
• [BUGFIX] jira: Allow disabling the resolve transition when resolve_transition is not set. #4821
• [BUGFIX] jira: Include unresolved issues in wont_fix_resolution JQL to prevent duplicate issue creation. #5185
• [BUGFIX] sns: Support the AWS_CA_BUNDLE env variable for the sns notifier. #5178

0.32.2 / 2026-06-05

• [BUGFIX] Fix dispatcher goroutine leaks on destroyed alertgroup swap. #5241

0.32.1 / 2026-04-29

• [BUGFIX] dispatcher: Fix issue with dispatching to a contended route. #5179
• [BUGFIX] ui: Provide prebuilt ui assets in release. #5191
• [ENHANCEMENT] ui: Support building artifacts in containers with Docker or Podman. #5102

0.32.1-rc.0 / 2026-04-27

• [BUGFIX] dispatcher: Fix issue with dispatching to a contended route. #5179
• [BUGFIX] ui: Provide prebuilt ui assets in release. #5191
• [ENHANCEMENT] ui: Support building artifacts in containers with Docker or Podman. #5102

0.32.0 / 2026-04-08

• [CHANGE] go get github.com/prometheus/alertmanager/ui will now fail as compiled UI assets are no longer checked into the repository. Downstream builds that rely on these assets being present in the source tree must now build the UI from source. #5113
• [CHANGE] The '--enable-feature=auto-gomaxprocs' option is deprecated and will be removed in v0.33. This flag currently has no effect and can be safely removed from any startup scripts. #5090
• [CHANGE] Update internal function signatures across multiple packages. This affects any project that integrates Alertmanager code.
• [ENHANCEMENT] Add static asset caching. #5113
• [ENHANCEMENT] Reduce memory allocations through pre-sizing collections and batch allocation. #5020
• [ENHANCEMENT] Replace help with documentation in navigation bar. #4943
• [ENHANCEMENT] docs(ha): Update high availability documentation. #5136
• [ENHANCEMENT] docs: Add auth_secret_file for smtp in document. #5036
• [ENHANCEMENT] docs: Add description for global telegram_bot_token. #5114
• [ENHANCEMENT] docs: Add note about notifier timeouts. #5077
• [ENHANCEMENT] docs: Fix force_implicit_tls config field name. #5030
• [ENHANCEMENT] docs: Link community supported integrations. #4978
• [ENHANCEMENT] docs: Remove duplicate header. #5034
• [ENHANCEMENT] docs: Update mutual tls reference in high availability documentation. #5120
• [ENHANCEMENT] tracing: Use noop spans when tracing disabled. #5118
• [ENHANCEMENT] ui: Serve pre-compressed assets. #5133
• [FEATURE] Add silence annotations. #4965
• [FEATURE] Add silence logging option. #4163
• [FEATURE] Add support for multiple matcher set silences. #4957
• [FEATURE] Add the reason for notifying in dedup stage. #4971
• [FEATURE] mattermost: Flatten attachments into top-level config. #5009
• [FEATURE] mattermost: Support global webhook url. #4998
• [FEATURE] slack: Add default color from template. #5014
• [FEATURE] slack: Allow receiver to edit existing messages. #5007
• [FEATURE] template: Add dict, map and append functions. #5093
• [FEATURE] webhook: Add full payload templating support for notifier. #5011
• [BUGFIX] config: Check for empty cluster tls client config. #5126
• [BUGFIX] config: Don't crash upon reading empty config for notifier. #4979
• [BUGFIX] config: Fix ipv6 address handling in hostport.string(). #5040
• [BUGFIX] mattermost: Omit empty text field in notifications. #4985
• [BUGFIX] telegram: Send fallback message when notification exceeds character limit. #5074
• [BUGFIX] tracing: Properly shutdown tracer provider. #5131
• [BUGFIX] ui: Fix escaping for matcher values with quotes. #4862
• [BUGFIX] ui: Handle special chars in silence regex-matchers. #4942
• [BUGFIX] ui: Support utf-8 label names in matchers. #5089

0.31.1 / 2026-02-11

• [BUGFIX] docs: Fix email TLS configuration example. #4976
• [BUGFIX] docs: Add telegram bot token options to global config docs. #4999

0.31.0 / 2026-02-02

• [ENHANCEMENT] docs(opsgenie): Fix description of api_url field. #4908
• [ENHANCEMENT] docs(slack): Document missing app configs. #4871
• [ENHANCEMENT] docs: Fix max-silence-size-bytes. #4805
• [ENHANCEMENT] docs: Update expr for AlertmanagerClusterFailedToSendAlerts to exclude value 0. #4872
• [ENHANCEMENT] docs: Use matchers for inhibit rules examples. #4131
• [ENHANCEMENT] docs: add notification integrations. #4901
• [ENHANCEMENT] docs: update slack_config attachments documentation links. #4802
• [ENHANCEMENT] docs: update description of filter query params in openapi doc. #4810
• [ENHANCEMENT] provider: Reduce lock contention. #4809
• [FEATURE] slack: Add support for top-level text field in slack notification. #4867
• [FEATURE] smtp: Add support for authsecret from file. #3087
• [FEATURE] smtp: Customize the ssl/tls port support (#4757). #4818
• [FEATURE] smtp: Enhance email notifier configuration validation. #4826
• [FEATURE] telegram: Add chat_id_file configuration parameter. #4909
• [FEATURE] telegram: Support global bot token. #4823
• [FEATURE] webhook: Support templating in url fields. #4798
• [FEATURE] wechat: Add config directive to pass api secret via file. #4734
• [FEATURE] provider: Implement per alert limits. #4819
• [BUGFIX] Allow empty group_by to override parent route. #4825
• [BUGFIX] Set spellcheck=false attribute on silence filter input. #4811
• [BUGFIX] jira: Fix for handling api v3 with ADF. #4756
• [BUGFIX] jira: Prevent hostname corruption in cloud api url replacement. #4892

0.30.1 / 2026-01-12

• [BUGFIX] Fix memory leak in tracing client. #4828