0.29.0 / 2025-11-01

• [FEATURE] Add incident.io notifier. #4372
• [FEATURE] Add monospace message formatting. #4362
• [FEATURE] Add ability to customize interval for maintenance to run. #4541
• [ENHANCEMENT] Update Jira notifier to support both Jira cloud API v3 and Jira datacenter API v2. #4542
• [ENHANCEMENT] Increase mixin rate intervals for alert FailedToSendAlerts. #4206
• [ENHANCEMENT] Make /alertmanager group writable in docker image. #4469
• [BUGFIX] Fix logged notification count on error in notify. #4323
• [BUGFIX] Fix docker image permissions path. #4288
• [BUGFIX] Fix error handling in template rendering for Telegram. #4353
• [BUGFIX] Fix duplicate other in error messages for config. #4366
• [BUGFIX] Fix logic that considers an alert reopened in Jira. #4478
• [BUGFIX] Fix Jira issue count #4615

0.29.0-rc.1 / 2025-10-12

• [FEATURE] Add incident.io notifier. #4372
• [FEATURE] Add monospace message formatting. #4362
• [FEATURE] Add ability to customize interval for maintenance to run. #4541
• [ENHANCEMENT] Update Jira notifier to support both Jira cloud API v3 and Jira datacenter API v2. #4542
• [ENHANCEMENT] Increase mixin rate intervals for alert FailedToSendAlerts. #4206
• [ENHANCEMENT] Make /alertmanager group writable in docker image. #4469
• [BUGFIX] Fix logged notification count on error in notify. #4323
• [BUGFIX] Fix docker image permissions path. #4288
• [BUGFIX] Fix error handling in template rendering for Telegram. #4353
• [BUGFIX] Fix duplicate other in error messages for config. #4366
• [BUGFIX] Fix logic that considers an alert reopened in Jira. #4478

0.28.1 / 2025-03-07

• [ENHANCEMENT] Improved performance of inhibition rules when using Equal labels. #4119
• [ENHANCEMENT] Improve the documentation on escaping in UTF-8 matchers. #4157
• [ENHANCEMENT] Update alertmanager_config_hash metric help to document the hash is not cryptographically strong. #4210
• [BUGFIX] Fix panic in amtool when using --verbose. #4218
• [BUGFIX] Fix templating of channel field for Rocket.Chat. #4220
• [BUGFIX] Fix rocketchat_configs written as rocket_configs in docs. #4217
• [BUGFIX] Fix usage for --enable-feature flag. #4214
• [BUGFIX] Trim whitespace from OpsGenie API Key. #4195
• [BUGFIX] Fix Jira project template not rendered when searching for existing issues. #4291
• [BUGFIX] Fix subtle bug in JSON/YAML encoding of inhibition rules that would cause Equal labels to be omitted. #4292
• [BUGFIX] Fix header for slack_configs in docs. #4247
• [BUGFIX] Fix weight and wrap of Microsoft Teams notifications. #4222
• [BUGFIX] Fix format of YAML examples in configuration.md. #4207

0.28.0 / 2025-01-15

• [CHANGE] Templating errors in the SNS integration now return an error. #3531 #3879
• [CHANGE] Adopt log/slog, drop go-kit/log #4089
• [FEATURE] Add a new Microsoft Teams integration based on Flows #4024
• [FEATURE] Add a new Rocket.Chat integration #3600
• [FEATURE] Add a new Jira integration #3590 #3931
• [FEATURE] Add support for GOMEMLIMIT, enable it via the feature flag --enable-feature=auto-gomemlimit. #3895
• [FEATURE] Add support for GOMAXPROCS, enable it via the feature flag --enable-feature=auto-gomaxprocs. #3837
• [FEATURE] Add support for limits of silences including the maximum number of active and pending silences, and the maximum size per silence (in bytes). You can use the flags --silences.max-silences and --silences.max-silence-size-bytes to set them accordingly #3852 #3862 #3866 #3885 #3886 #3877
• [FEATURE] Muted alerts now show whether they are suppressed or not in both the /api/v2/alerts endpoint and the Alertmanager UI. #3793 #3797 #3792
• [ENHANCEMENT] Add support for content, username and avatar_url in the Discord integration. content and username also support templating. #4007
• [ENHANCEMENT] Only invalidate the silences cache if a new silence is created or an existing silence replaced - should improve latency on both GET api/v2/alerts and POST api/v2/alerts API endpoint. #3961
• [ENHANCEMENT] Add image source label to Dockerfile. To get changelogs shown when using Renovate #4062
• [ENHANCEMENT] Build using go 1.23 #4071
• [ENHANCEMENT] Support setting a global SMTP TLS configuration. #3732
• [ENHANCEMENT] The setting room_id in the WebEx integration can now be templated to allow for dynamic room IDs. #3801
• [ENHANCEMENT] Enable setting message_thread_id for the Telegram integration. #3638
• [ENHANCEMENT] Support the since and humanizeDuration functions to templates. This means users can now format time to more human-readable text. #3863
• [ENHANCEMENT] Support the date and tz functions to templates. This means users can now format time in a specified format and also change the timezone to their specific locale. #3812
• [ENHANCEMENT] Latency metrics now support native histograms. #3737
• [ENHANCEMENT] Add full width to adaptive card for msteamsv2 #4135
• [ENHANCEMENT] Add timeout option for webhook notifier. #4137
• [ENHANCEMENT] Update config to allow showing secret values when marshaled #4158
• [ENHANCEMENT] Enable templating for Jira project and issue_type #4159
• [BUGFIX] Fix the SMTP integration not correctly closing an SMTP submission, which may lead to unsuccessful dispatches being marked as successful. #4006
• [BUGFIX] The ParseMode option is now set explicitly in the Telegram integration. If we don't HTML tags had not been parsed by default. #4027
• [BUGFIX] Fix a memory leak that was caused by updates silences continuously. #3930
• [BUGFIX] Fix hiding secret URLs when the URL is incorrect. #3887
• [BUGFIX] Fix a race condition in the alerts - it was more of a hypothetical race condition that could have occurred in the alert reception pipeline. #3648
• [BUGFIX] Fix a race condition in the alert delivery pipeline that would cause a firing alert that was delivered earlier to be deleted from the aggregation group when instead it should have been delivered again. #3826
• [BUGFIX] Fix version in APIv1 deprecation notice. #3815
• [BUGFIX] Fix crash errors when using url_file in the Webhook integration. #3800
• [BUGFIX] fix Route.ID() returns conflicting IDs. #3803
• [BUGFIX] Fix deadlock on the alerts memory store. #3715
• [BUGFIX] Fix amtool template render when using the default values. #3725
• [BUGFIX] Fix webhook_url_file for both the Discord and Microsoft Teams integrations. #3728 #3745
• [BUGFIX] Fix wechat api link #4084
• [BUGFIX] Fix build info metric #4166
• [BUGFIX] Fix UTF-8 not allowed in Equal field for inhibition rules #4177

0.28.0-rc.0 / 2024-10-24

• [CHANGE] Templating errors in the SNS integration now return an error. #3531 #3879
• [FEATURE] Add a new Microsoft Teams integration based on Flows #4024
• [FEATURE] Add a new Rocket.Chat integration #3600
• [FEATURE] Add a new Jira integration #3590 #3931
• [FEATURE] Add support for GOMEMLIMIT, enable it via the feature flag --enable-feature=auto-gomemlimit. #3895
• [FEATURE] Add support for GOMAXPROCS, enable it via the feature flag --enable-feature=auto-gomaxprocs. #3837
• [FEATURE] Add support for limits of silences including the maximum number of active and pending silences, and the maximum size per silence (in bytes). You can use the flags --silences.max-silences and --silences.max-silence-size-bytes to set them accordingly #3852 #3862 #3866 #3885 #3886 #3877
• [FEATURE] Muted alerts now show whether they are suppressed or not in both the /api/v2/alerts endpoint and the Alertmanager UI. #3793 #3797 #3792
• [ENHANCEMENT] Add support for content, username and avatar_url in the Discord integration. content and username also support templating. #4007
• [ENHANCEMENT] Only invalidate the silences cache if a new silence is created or an existing silence replaced - should improve latency on both GET api/v2/alerts and POST api/v2/alerts API endpoint. #3961
• [ENHANCEMENT] Add image source label to Dockerfile. To get changelogs shown when using Renovate #4062
• [ENHANCEMENT] Build using go 1.23 #4071
• [ENHANCEMENT] Support setting a global SMTP TLS configuration. #3732
• [ENHANCEMENT] The setting room_id in the WebEx integration can now be templated to allow for dynamic room IDs. #3801
• [ENHANCEMENT] Enable setting message_thread_id for the Telegram integration. #3638
• [ENHANCEMENT] Support the since and humanizeDuration functions to templates. This means users can now format time to more human-readable text. #3863
• [ENHANCEMENT] Support the date and tz functions to templates. This means users can now format time in a specified format and also change the timezone to their specific locale. #3812
• [ENHANCEMENT] Latency metrics now support native histograms. #3737
• [BUGFIX] Fix the SMTP integration not correctly closing an SMTP submission, which may lead to unsuccessful dispatches being marked as successful. #4006
• [BUGFIX] The ParseMode option is now set explicitly in the Telegram integration. If we don't HTML tags had not been parsed by default. #4027
• [BUGFIX] Fix a memory leak that was caused by updates silences continuously. #3930
• [BUGFIX] Fix hiding secret URLs when the URL is incorrect. #3887
• [BUGFIX] Fix a race condition in the alerts - it was more of a hypothetical race condition that could have occurred in the alert reception pipeline. #3648
• [BUGFIX] Fix a race condition in the alert delivery pipeline that would cause a firing alert that was delivered earlier to be deleted from the aggregation group when instead it should have been delivered again. #3826
• [BUGFIX] Fix version in APIv1 deprecation notice. #3815
• [BUGFIX] Fix crash errors when using url_file in the Webhook integration. #3800
• [BUGFIX] fix Route.ID() returns conflicting IDs. #3803
• [BUGFIX] Fix deadlock on the alerts memory store. #3715
• [BUGFIX] Fix amtool template render when using the default values. #3725
• [BUGFIX] Fix webhook_url_file for both the Discord and Microsoft Teams integrations. #3728 #3745

0.27.0 / 2024-02-28

• [CHANGE] Discord Integration: Enforce max length in message. #3597
• [CHANGE] API: Removal of all api/v1/ endpoints. These endpoints now log and return a deprecation message and respond with a status code of 410. #2970
• [FEATURE] UTF-8 Support: Introduction of support for any UTF-8 character as part of label names and matchers. Please read more below. #3453, #3483, #3567, #3570
• [FEATURE] Metrics: Introduced the experimental feature flag --enable-feature=receiver-name-in-metrics to include the receiver name in the following metrics: #3045
  • alertmanager_notifications_total
  • alertmanager_notifications_failed_totall
  • alertmanager_notification_requests_total
  • alertmanager_notification_requests_failed_total
  • alertmanager_notification_latency_seconds
• [FEATURE] Metrics: Introduced a new gauge named alertmanager_inhibition_rules that counts the number of configured inhibition rules. #3681
• [FEATURE] Metrics: Introduced a new counter named alertmanager_alerts_supressed_total that tracks muted alerts, it contains a reason label to indicate the source of the mute. #3565
• [ENHANCEMENT] Discord Integration: Introduced support for webhook_url_file. #3555
• [ENHANCEMENT] Microsoft Teams Integration: Introduced support for webhook_url_file. #3555
• [ENHANCEMENT] Microsoft Teams Integration: Add support for summary. #3616
• [ENHANCEMENT] Metrics: Notification metrics now support two new values for the label reason, contextCanceled and contextDeadlineExceeded. #3631
• [ENHANCEMENT] Email Integration: Contents of auth_password_file are now trimmed of prefixed and suffixed whitespace. #3680
• [BUGFIX] amtool: Fixes the error scheme required for webhook url when using amtool with --alertmanager.url. #3509
• [BUGFIX] Mixin: Fix AlertmanagerFailedToSendAlerts, AlertmanagerClusterFailedToSendAlerts, and AlertmanagerClusterFailedToSendAlerts to make sure they ignore the reason label. #3599

Removal of API v1

The Alertmanager v1 API has been deprecated since January 2019 with the release of Alertmanager v0.16.0. With the release of version 0.27.0 it is now removed.
A successful HTTP request to any of the v1 endpoints will log and return a deprecation message while responding with a status code of 410.
Please ensure you switch to the v2 equivalent endpoint in your integrations before upgrading.

Alertmanager support for all UTF-8 characters in matchers and label names

Starting with Alertmanager v0.27.0, we have a new parser for matchers that has a number of backwards incompatible changes. While most matchers will be forward-compatible, some will not. Alertmanager is operating a transition period where it supports both UTF-8 and classic matchers, so it's entirely safe to upgrade without any additional configuration. With that said, we recommend the following:

• If this is a new Alertmanager installation, we recommend enabling UTF-8 strict mode before creating an Alertmanager configuration file. You can enable strict mode with alertmanager --config.file=config.yml --enable-feature="utf8-strict-mode".

• If this is an existing Alertmanager installation, we recommend running the Alertmanager in the default mode called fallback mode before enabling UTF-8 strict mode. In this mode, Alertmanager will log a warning if you need to make any changes to your configuration file before UTF-8 strict mode can be enabled. Alertmanager will make UTF-8 strict mode the default in the next two versions, so it's important to transition as soon as possible.

Irrespective of whether an Alertmanager installation is a new or existing installation, you can also use amtool to validate that an Alertmanager configuration file is compatible with UTF-8 strict mode before enabling it in Alertmanager server by running amtool check-config config.yml and inspecting the log messages.

Should you encounter any problems, you can run the Alertmanager with just the classic parser enabled by running alertmanager --config.file=config.yml --enable-feature="classic-mode". If so, please submit a bug report via GitHub issues.

0.27.0-rc.0 / 2024-02-14

• [CHANGE] Discord Integration: Enforce max length in message. #3597
• [CHANGE] API: Removal of all api/v1/ endpoints. These endpoints now log and return a deprecation message and respond with a status code of 410. #2970
• [FEATURE] UTF-8 Support: Introduction of support for any UTF-8 character as part of label names and matchers. Please read more below. #3453, #3483, #3567, #3570
• [FEATURE] Metrics: Introduced the experimental feature flag --enable-feature=receiver-name-in-metrics to include the receiver name in the following metrics: #3045
  • alertmanager_notifications_total
  • alertmanager_notifications_failed_totall
  • alertmanager_notification_requests_total
  • alertmanager_notification_requests_failed_total
  • alertmanager_notification_latency_seconds
• [FEATURE] Metrics: Introduced a new gauge named alertmanager_inhibition_rules that counts the number of configured inhibition rules. #3681
• [FEATURE] Metrics: Introduced a new counter named alertmanager_alerts_supressed_total that tracks muted alerts, it contains a reason label to indicate the source of the mute. #3565
• [ENHANCEMENT] Discord Integration: Introduced support for webhook_url_file. #3555
• [ENHANCEMENT] Microsoft Teams Integration: Introduced support for webhook_url_file. #3555
• [ENHANCEMENT] Microsoft Teams Integration: Add support for summary. #3616
• [ENHANCEMENT] Metrics: Notification metrics now support two new values for the label reason, contextCanceled and contextDeadlineExceeded. #3631
• [ENHANCEMENT] Email Integration: Contents of auth_password_file are now trimmed of prefixed and suffixed whitespace. #3680
• [BUGFIX] amtool: Fixes the error scheme required for webhook url when using amtool with --alertmanager.url. #3509
• [BUGFIX] Mixin: Fix AlertmanagerFailedToSendAlerts, AlertmanagerClusterFailedToSendAlerts, and AlertmanagerClusterFailedToSendAlerts to make sure they ignore the reason label. #3599

Removal of API v1

The Alertmanager v1 API has been deprecated since January 2019 with the release of Alertmanager v0.16.0. With the release of version 0.27.0 it is now removed.
A successful HTTP request to any of the v1 endpoints will log and return a deprecation message while responding with a status code of 410.
Please ensure you switch to the v2 equivalent endpoint in your integrations before upgrading.

Alertmanager support for all UTF-8 characters in matchers and label names

Starting with Alertmanager v0.27.0, we have a new parser for matchers that has a number of backwards incompatible changes. While most matchers will be forward-compatible, some will not. Alertmanager is operating a transition period where it supports both UTF-8 and classic matchers, so it's entirely safe to upgrade without any additional configuration. With that said, we recommend the following:

• If this is a new Alertmanager installation, we recommend enabling UTF-8 strict mode before creating an Alertmanager configuration file. You can enable strict mode with alertmanager --config.file=config.yml --enable-feature="utf8-strict-mode".

• If this is an existing Alertmanager installation, we recommend running the Alertmanager in the default mode called fallback mode before enabling UTF-8 strict mode. In this mode, Alertmanager will log a warning if you need to make any changes to your configuration file before UTF-8 strict mode can be enabled. Alertmanager will make UTF-8 strict mode the default in the next two versions, so it's important to transition as soon as possible.

Irrespective of whether an Alertmanager installation is a new or existing installation, you can also use amtool to validate that an Alertmanager configuration file is compatible with UTF-8 strict mode before enabling it in Alertmanager server by running amtool check-config config.yml and inspecting the log messages.

Should you encounter any problems, you can run the Alertmanager with just the classic parser enabled by running alertmanager --config.file=config.yml --enable-feature="classic-mode". If so, please submit a bug report via GitHub issues.

0.26.0 / 2023-08-23

• [SECURITY] Fix stored XSS via the /api/v1/alerts endpoint in the Alertmanager UI.
• [CHANGE] Telegram Integration: api_url is now optional. #2981
• [CHANGE] Telegram Integration: ParseMode default is now HTML instead of MarkdownV2. #2981
• [CHANGE] Webhook Integration: url is now marked as a secret. It will no longer show up in the logs as clear-text. #3228
• [CHANGE] Metrics: New label reason for alertmanager_notifications_failed_total metric to indicate the type of error of the alert delivery. #3094 #3307
• [FEATURE] Clustering: New flag --cluster.label, to help to block any traffic that is not meant for the cluster. #3354
• [FEATURE] Integrations: Add Microsoft Teams as a supported integration. #3324
• [ENHANCEMENT] Telegram Integration: Support bot_token_file for loading this secret from a file. #3226
• [ENHANCEMENT] Webhook Integration: Support url_file for loading this secret from a file. #3223
• [ENHANCEMENT] Webhook Integration: Leading and trailing white space is now removed for the contents of url_file. #3363
• [ENHANCEMENT] Pushover Integration: Support options device and sound (sound was previously supported but undocumented). #3318
• [ENHANCEMENT] Pushover Integration: Support user_key_file and token_file for loading this secret from a file. #3200
• [ENHANCEMENT] Slack Integration: Support errors wrapped in successful (HTTP status code 200) responses. #3121
• [ENHANCEMENT] API: Add CORS and Cache-Control HTTP headers to all version 2 API routes. #3195
• [ENHANCEMENT] UI: Receiver name is now visible as part of the alerts page. #3289
• [ENHANCEMENT] Templating: Better default text when using {{ .Annotations }} and {{ .Labels }}. #3256
• [ENHANCEMENT] Templating: Introduced a new function trimSpace which removes leading and trailing white spaces. #3223
• [ENHANCEMENT] CLI: amtool silence query now supports the --id flag to query an individual silence. #3241
• [ENHANCEMENT] Metrics: Introduced alertmanager_nflog_maintenance_total and alertmanager_nflog_maintenance_errors_total to monitor maintenance of the notification log. #3286
• [ENHANCEMENT] Metrics: Introduced alertmanager_silences_maintenance_total and alertmanager_silences_maintenance_errors_total to monitor maintenance of silences. #3285
• [ENHANCEMENT] Logging: Log GroupKey and alerts on alert delivery when using debug mode. #3438
• [BUGFIX] Configuration: Empty list of receivers and inhibit_rules would cause the alertmanager to crash. #3209
• [BUGFIX] Templating: Fixed a race condition when using the title function. It is now race-safe. #3278
• [BUGFIX] API: Fixed duplicate receiver names in the api/v2/receivers API endpoint. #3338
• [BUGFIX] API: Attempting to delete a silence now returns the correct status code, 404 instead of 500. #3352
• [BUGFIX] Clustering: Fixes a panic when tls_client_config is empty. #3443

0.25.1 / 2023-08-23

• [SECURITY] Fix stored XSS via the /api/v1/alerts endpoint in the Alertmanager UI (CVE-2023-40577).

0.26.0-rc.0 / 2023-08-17

• [CHANGE] Telegram Integration: api_url is now optional. #2981
• [CHANGE] Telegram Integration: ParseMode default is now HTML instead of MarkdownV2. #2981
• [CHANGE] Webhook Integration: url is now marked as a secret. It will no longer show up in the logs as clear-text. #3228
• [CHANGE] Metrics: New label reason for alertmanager_notifications_failed_total metric to indicate the type of error of the alert delivery. #3094 #3307
• [FEATURE] Clustering: New flag --cluster.label, to help to block any traffic that is not meant for the cluster. #3354
• [FEATURE] Integrations: Add Microsoft Teams as a supported integration. #3324
• [ENHANCEMENT] Telegram Integration: Support bot_token_file for loading this secret from a file. #3226
• [ENHANCEMENT] Webhook Integration: Support url_file for loading this secret from a file. #3223
• [ENHANCEMENT] Webhook Integration: Leading and trailing white space is now removed for the contents of url_file. #3363
• [ENHANCEMENT] Pushover Integration: Support options device and sound (sound was previously supported but undocumented). #3318
• [ENHANCEMENT] Pushover Integration: Support user_key_file and token_file for loading this secret from a file. #3200
• [ENHANCEMENT] Slack Integration: Support errors wrapped in successful (HTTP status code 200) responses. #3121
• [ENHANCEMENT] API: Add CORS and Cache-Control HTTP headers to all version 2 API routes. #3195
• [ENHANCEMENT] UI: Receiver name is now visible as part of the alerts page. #3289
• [ENHANCEMENT] Templating: Better default text when using {{ .Annotations }} and {{ .Labels }}. #3256
• [ENHANCEMENT] Templating: Introduced a new function trimSpace which removes leading and trailing white spaces. #3223
• [ENHANCEMENT] CLI: amtool silence query now supports the --id flag to query an individual silence. #3241
• [ENHANCEMENT] Metrics: Introduced alertmanager_nflog_maintenance_total and alertmanager_nflog_maintenance_errors_total to monitor maintenance of the notification log. #3286
• [ENHANCEMENT] Metrics: Introduced alertmanager_silences_maintenance_total and alertmanager_silences_maintenance_errors_total to monitor maintenance of silences. #3285
• [ENHANCEMENT] Logging: Log GroupKey and alerts on alert delivery when using debug mode. #3438
• [BUGFIX] Configuration: Empty list of receivers and inhibit_rules would cause the alertmanager to crash. #3209
• [BUGFIX] Templating: Fixed a race condition when using the title function. It is now race-safe. #3278
• [BUGFIX] API: Fixed duplicate receiver names in the api/v2/receivers API endpoint. #3338
• [BUGFIX] API: Attempting to delete a silence now returns the correct status code, 404 instead of 500. #3352
• [BUGFIX] Clustering: Fixes a panic when tls_client_config is empty. #3443