code · pull · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026
diff --git a/NOTICE.txt b/NOTICE.txt
@@ -5933,38 +5933,6 @@ Redistribution and use in source and binary forms, with or without modification,
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
----
-
-## go-mail/mail
-
-This product contains 'go-mail/mail' by go-mail.
-
-Actively maintained fork of gomail. The best way to send emails in Go.
-
-* LICENSE: MIT License
-
-The MIT License (MIT)
-
-Copyright (c) 2014 Alexandre Cesaro
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
-the Software, and to permit persons to whom the Software is furnished to do so,
-subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
-FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
-COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
-IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-
 ---
 
 ## goccy/go-yaml
@@ -7494,6 +7462,43 @@ This product contains 'isacikgoz/prompt' by Ibrahim Serdar Acikgoz.
   * https://github.com/isacikgoz/prompt
 
 
+---
+
+## jaytaylor/html2text
+
+This product contains 'jaytaylor/html2text' by Jay Taylor.
+
+Golang HTML to plaintext conversion library
+
+* HOMEPAGE:
+  * https://jaytaylor.com/html2text
+
+* LICENSE: MIT License
+
+The MIT License (MIT)
+
+Copyright (c) 2015 Jay Taylor
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+
+
 ---
 
 ## jmoiron/sqlx
@@ -13516,6 +13521,42 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 
 
+---
+
+## wneessen/go-mail
+
+This product contains 'wneessen/go-mail' by Winni Neessen.
+
+📧 Easy to use, yet comprehensive library for sending mails with Go
+
+* HOMEPAGE:
+  * https://go-mail.dev
+
+* LICENSE: MIT License
+
+MIT License
+
+Copyright (c) 2022-2025 The go-mail Authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+
 ---
 
 ## x/crypto

diff --git a/...dministration-guide/scale/common-configure-mattermost-for-enterprise-search.mdx b/...dministration-guide/scale/common-configure-mattermost-for-enterprise-search.mdx
@@ -38,7 +38,7 @@ For high post volume deployments, we strongly encourage you to read and properly
 
 <Warning>
 
-For high post volume deployments, we also strongly recommend *disabling* Database Search once Elasticsearch or AWS OpenSearch is fully configured and running. The Mattermost Server will fall back on Database search if ElasticSearch or OpenSearch are unavailable which can lead to performance degradation on high post volume deployments.
+For high post volume deployments, we also strongly recommend *disabling* Database Search once Elasticsearch or AWS OpenSearch is fully configured and running. The Mattermost Server will fall back on Database search if Elasticsearch or OpenSearch are unavailable, which can lead to performance degradation on high post volume deployments. From Mattermost v11.7, the server proactively detects outages through periodic health checks and falls back to database search on the first health check failure, rather than waiting for requests to time out. See the [outage handling FAQ](/administration-guide/scale/enterprise-search#how-does-mattermost-handle-elasticsearch-or-opensearch-outages) for details.
 
 </Warning>
 

diff --git a/...nistration-guide/scale/deploy-prometheus-grafana-for-performance-monitoring.mdx b/...nistration-guide/scale/deploy-prometheus-grafana-for-performance-monitoring.mdx
@@ -129,6 +129,8 @@ See [this Grafana guide](https://grafana.com/docs/grafana/v7.5/dashboards/export
 
 Mattermost provides [custom metrics](/administration-guide/scale/performance-monitoring-metrics#custom-mattermost-metrics) and [standard Go metrics](/administration-guide/scale/performance-monitoring-metrics#standard-go-metrics) that can be used to monitor your system's performance.
 
+When the `AggregatePluginMetrics` feature flag is enabled, plugin-provided metrics are included in the same `/metrics` scrape target and can be filtered by the `plugin_id` label.
+
 ## Next steps
 
 Once you've set up performance monitoring, you may want to:

diff --git a/docs/main/administration-guide/scale/elasticsearch-setup.mdx b/docs/main/administration-guide/scale/elasticsearch-setup.mdx
@@ -13,7 +13,7 @@ Deploying Elasticsearch includes the following two steps: [setting up Elasticsea
 
 We highly recommend that you set up Elasticsearch server on a dedicated machine separate from the Mattermost Server.
 
-1.  Download and install the latest release of [Elasticsearch v8](https://www.elastic.co/guide/en/elasticsearch/reference/8.15/install-elasticsearch.html), or [Elasticsearch v7.17+](https://www.elastic.co/guide/en/elasticsearch/reference/7.17/install-elasticsearch.html). See the Elasticsearch documentation for installation details.
+1.  Download and install the latest release of [Elasticsearch v9](https://www.elastic.co/guide/en/elasticsearch/reference/current/install-elasticsearch.html) or [Elasticsearch v8](https://www.elastic.co/guide/en/elasticsearch/reference/8.19/install-elasticsearch.html). See the Elasticsearch documentation for installation details.
 2.  Set up Elasticsearch with `systemd` by running the following commands:
 
 > ``` sh
@@ -41,7 +41,7 @@ We highly recommend that you set up Elasticsearch server on a dedicated machine
 > ```
 
 6.  In this file, replace the `network.host` value of `_eth0_` with your network interface name, and save your changes.
-7.  When using Elasticsearch v8, ensure you set `action.destructive_requires_name` to `false` in `elasticsearch.yml` to allow for wildcard operations to work.
+7.  Ensure you set `action.destructive_requires_name` to `false` in `elasticsearch.yml` to allow for wildcard operations to work.
 8.  Restart Elasticsearch by running the following commands:
 
 > ``` sh

diff --git a/docs/main/administration-guide/scale/enterprise-search.mdx b/docs/main/administration-guide/scale/enterprise-search.mdx
@@ -29,9 +29,20 @@ The AWS OpenSearch Service is built on the open-source OpenSearch project, which
 Review the following support paths for enterprise search based on the version you're using:
 
 <Tabs>
+<TabItem value="elasticsearch-v9" label="Elasticsearch v9">
+
+[Elasticsearch v9](https://www.elastic.co/guide/en/elasticsearch/reference/current/elasticsearch-intro.html) is supported from Mattermost v11.7. We recommend upgrading to Elasticsearch v9 for the latest features and security updates. See the [Elasticsearch upgrade](https://www.elastic.co/guide/en/elasticsearch/reference/current/setup-upgrade.html) documentation for upgrade details, and see the [Elasticsearch setup](/administration-guide/scale/elasticsearch-setup) documentation for details on configuring your Mattermost deployment to use Elasticsearch.
+
+</TabItem>
 <TabItem value="elasticsearch-v8" label="Elasticsearch v8">
 
-[Elasticsearch v8](https://www.elastic.co/guide/en/elasticsearch/reference/current/elasticsearch-intro.html) is supported from Mattermost v9.11. While Mattermost supports Elasticsearch v7.17+, we recommend upgrading your Elasticsearch v7 instance to v8.x. See the [Elasticsearch upgrade](https://www.elastic.co/guide/en/elasticsearch/reference/current/setup-upgrade.html) documentation for upgrade details, and see the [Elasticsearch setup](/administration-guide/scale/elasticsearch-setup) documentation for details on configuring your Mattermost deployment to use Elasticsearch.
+[Elasticsearch v8](https://www.elastic.co/guide/en/elasticsearch/reference/8.19/elasticsearch-intro.html) is supported from Mattermost v9.11. We recommend upgrading to Elasticsearch v9 for the latest features and security updates. See the [Elasticsearch upgrade](https://www.elastic.co/guide/en/elasticsearch/reference/current/setup-upgrade.html) documentation for upgrade details, and see the [Elasticsearch setup](/administration-guide/scale/elasticsearch-setup) documentation for details on configuring your Mattermost deployment to use Elasticsearch.
+
+<Note>
+
+Elasticsearch v7.17 is no longer supported as of Mattermost v11.7. If you're still using Elasticsearch v7, you must upgrade to Elasticsearch v8 or v9.
+
+</Note>
 
 </TabItem>
 <TabItem value="aws-opensearch-service" label="AWS OpenSearch Service">
@@ -43,13 +54,13 @@ See the **AWS Elasticsearch v7.10.x** tab on this page for details on upgrading
 </TabItem>
 <TabItem value="aws-elasticsearch-v7-10-x" label="AWS Elasticsearch v7.10.x">
 
-If you're using Elasticsearch v7.10.x under AWS’s managed services, you can't use newer Elasticsearch clients like the v8 client without changing backend infrastructure. If you're using AWS Elasticsearch v7.10.x, you must [upgrade to AWS OpenSearch](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/version-migration.html) for future compatibility.
+If you're using Elasticsearch v7.10.x under AWS’s managed services, you can't use newer Elasticsearch clients like the v8 or v9 client without changing backend infrastructure. If you're using AWS Elasticsearch v7.10.x, you must [upgrade to AWS OpenSearch](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/version-migration.html) for future compatibility.
 
 The migration path from Elasticsearch v7.10.x to OpenSearch has been designed to be straightforward, minimizing effort:
 
 1.  Disable "compatibility mode" in OpenSearch.
 2.  Upgrade Mattermost server.
-3.  Update the Mattermost `ElasticsearchSettings.Backend` configuration setting value from `elasticsearch` to `` `opensearch ``<code> manually or using \`mmctl \<mm-ref:administration-guide%2Fmanage%2Fmmctl-command-line-tool%3Ammctl%20config%20set\></code>\_\_. This value cannot be changed using the System Console. See the Mattermost search [backend type](/administration-guide/configure/environment-configuration-settings#backend-type) configuration setting documentation for additional details.
+3.  Update the Mattermost `ElasticsearchSettings.Backend` configuration setting value from `elasticsearch` to `opensearch` manually or using [mmctl](/administration-guide/manage/mmctl-command-line-tool#mmctl-config-set). This value cannot be changed using the System Console. See the Mattermost search [backend type](/administration-guide/configure/environment-configuration-settings#backend-type) configuration setting documentation for additional details.
 4.  Restart the Mattermost server.
 
 </TabItem>
@@ -114,6 +125,29 @@ From Mattermost v11, [Support Packet generation](/administration-guide/manage/ad
 
 The enterprise search connection test results appear in the Support Packet and can help identify configuration issues such as network connectivity problems, authentication failures, or server availability issues. If connection errors are present, they will be clearly documented with specific error messages to aid in troubleshooting.
 
+### How does Mattermost handle Elasticsearch or OpenSearch outages?
+
+From Mattermost v11.7, the server includes an automatic health monitor for Elasticsearch and OpenSearch connections. The health monitor runs periodic health checks and automatically manages the connection lifecycle:
+
+- **Health checks**: The server checks the health of the search engine cluster every 60 seconds. After 3 consecutive health check failures, the engine is stopped and search falls back to the database.
+- **Fast-fail on first failure**: On the very first health check failure, the engine is immediately marked as unhealthy and search requests are routed to the database. This happens before the consecutive failure threshold is reached, so users experience minimal disruption.
+- **Automatic retry**: When the search engine is unavailable, the server retries connecting with exponential backoff, starting at 15 seconds and doubling up to a maximum of 5 minutes between attempts.
+- **Automatic recovery**: When the search engine becomes available again, the server automatically reconnects and resumes using it for search queries. No manual intervention or server restart is required.
+- **Configuration changes**: Changes to Elasticsearch or OpenSearch configuration settings, or license changes, immediately trigger the health monitor to re-evaluate the connection state.
+- **Monitoring**: A `mattermost_search_engine_status` Prometheus metric reports the health of the search engine (`1` = healthy or not configured, `0` = configured but unavailable). Use this metric to [set up alerts](/administration-guide/scale/performance-alerting) for search engine outages. See [performance monitoring metrics](/administration-guide/scale/performance-monitoring-metrics) for details.
+
+During an outage, you may see the following log messages:
+
+| Level | Log message | Meaning |
+|---|---|---|
+| Error | `Search engine health check failed repeatedly; stopping engine` | The failure threshold was reached and the engine has been stopped. Search falls back to the database. |
+| Warn | `Search engine health check failed` | An individual health check failed. Includes a `consecutive_failures` count. |
+| Warn | `Search engine health check failed: it is now marked as unhealthy` | A previously healthy engine failed a health check and has been marked unhealthy. Search requests will fall back to the database immediately. |
+| Warn | `Search engine watcher: Start() failed, will retry` | A reconnection attempt failed. Includes a `next_backoff` field indicating the time until the next retry. |
+| Info | `Search engine health check succeeded: it is now marked as healthy` | The engine passed a health check after being unhealthy and is now handling search requests again. |
+| Info | `Search engine watcher: engine started successfully` | The engine has recovered and is active again. |
+| Info | `Search engine watcher: engine disabled, parking` | The health monitor is idle because the search engine is disabled in configuration. |
+
 ### My search indexes won't complete, what should I do?
 
 If you have an search indexing job that's paused, it's likely your Elasticsearch or OpenSearch server has restarted. If you restart that server, you must also restart Mattermost to ensure jobs are completed. If restarting the Mattermost server does not resolve the issue, [customers with a Mattermost subscription can contact Mattermost Support](https://mattermost.com/support/) for assistance.

diff --git a/docs/main/administration-guide/scale/opensearch-setup.mdx b/docs/main/administration-guide/scale/opensearch-setup.mdx
@@ -18,6 +18,12 @@ From Mattermost v9.11, beta support is available for [AWS OpenSearch v1.x and v2
 
 We highly recommend that you set up an AWS OpenSearch server on a separate machine from the Mattermost server.
 
+<Important>
+
+Starting in Mattermost v12.0 (October 2026), OpenSearch v1.x is no longer supported. Upgrading to OpenSearch v2.x or later is required.
+
+</Important>
+
 <Tabs>
 <TabItem value="on-premises-opensearch" label="On-Premises OpenSearch">
 
@@ -198,20 +204,25 @@ Port 9200 is commonly used for local or on-premise OpenSearch. The AWS OpenSearc
 
 </Note>
 
-5.  Configure the access policy (JSON):
+5.  Configure the access policy (JSON). Mattermost doesn't sign OpenSearch requests with AWS SigV4, so restrict access at the network layer with the VPC and security group from step 4, and use an open principal in the domain access policy:
 
 > ``` sh
 > &#123;
->   "Version": "2012-10-17", 
->   "Statement": [&#123; 
->     "Effect": "Allow", 
->     "Principal": &#123; "AWS": 
-> "arn:aws:iam::123456789012:role/MattermostAppRole" &#125;, 
->     "Action": "es:*", 
->     "Resource": "arn:aws:es:us-east-1:123456789012:domain/mattermost-os/*" &#125;] 
+>   "Version": "2012-10-17",
+>   "Statement": [&#123;
+>     "Effect": "Allow",
+>     "Principal": &#123; "AWS": "*" &#125;,
+>     "Action": "es:ESHttp*",
+>     "Resource": "arn:aws:es:us-east-1:123456789012:domain/mattermost-os/*" &#125;]
 > &#125;
 > ```
 
+<Warning>
+
+IAM principal-based access policies (for example, `"Principal": { "AWS": "arn:aws:iam::<account-id>:role/<role-name>" }`) are not supported. Mattermost's OpenSearch client doesn't sign requests with AWS SigV4, so AWS treats the requests as anonymous and an IAM-restricted policy will reject them with `User: anonymous is not authorized to perform: es:ESHttpGet`. If you need authentication enforced at the OpenSearch layer rather than the network layer, enable [fine-grained access control](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/fgac.html) on the domain with an internal master user, and enter those credentials as the **Server Username** and **Server Password** in the Mattermost Elasticsearch configuration.
+
+</Warning>
+
 6.  Configure the following advanced settings (JSON):
 
 > ``` sh
@@ -284,13 +295,13 @@ Port 9200 is commonly used for local or on-premise OpenSearch. The AWS OpenSearc
 >
 >   access_policies = &lt;<POLICY 
 > &#123;
->   "Version": "2012-10-17", 
->   "Statement": [&#123; 
->     "Effect": "Allow", 
->     "Principal": &#123; 
->       "AWS": "arn:aws:iam::123456789012:role/MattermostAppRole" 
+>   "Version": "2012-10-17",
+>   "Statement": [&#123;
+>     "Effect": "Allow",
+>     "Principal": &#123;
+>       "AWS": "*"
 >     &#125;,
->       "Action": "es:*", 
+>       "Action": "es:ESHttp*",
 >       "Resource": "arn:aws:es:us-east-1:123456789012:domain/mattermost-os/*" 
 >     &#125;]
 >   &#125;