diff --git a/net-mgmt/telegraf/Makefile b/net-mgmt/telegraf/Makefile
index 8217de4b1..cc1d6f967 100644
--- a/net-mgmt/telegraf/Makefile
+++ b/net-mgmt/telegraf/Makefile
@@ -1,5 +1,5 @@
 PLUGIN_NAME=		telegraf
-PLUGIN_VERSION=		1.12.14
+PLUGIN_VERSION=		1.12.15
 PLUGIN_COMMENT=		Agent for collecting metrics and data
 PLUGIN_DEPENDS=		telegraf
 PLUGIN_MAINTAINER=	m.muenz@gmail.com
diff --git a/net-mgmt/telegraf/pkg-descr b/net-mgmt/telegraf/pkg-descr
index 367925c76..a5dae08ef 100644
--- a/net-mgmt/telegraf/pkg-descr
+++ b/net-mgmt/telegraf/pkg-descr
@@ -12,6 +12,11 @@ WWW: https://www.influxdata.com/time-series-platform/telegraf/
 Plugin Changelog
 ================
 
+1.12.15
+
+* Add custom header support for OpenTelemetry output
+* Quote OpenTelemetry service_address in config
+
 1.12.14
 
 * Add name_prefix in influxdb config
diff --git a/net-mgmt/telegraf/src/opnsense/mvc/app/controllers/OPNsense/Telegraf/forms/output.xml b/net-mgmt/telegraf/src/opnsense/mvc/app/controllers/OPNsense/Telegraf/forms/output.xml
index ba6b50c21..9f79ea655 100644
--- a/net-mgmt/telegraf/src/opnsense/mvc/app/controllers/OPNsense/Telegraf/forms/output.xml
+++ b/net-mgmt/telegraf/src/opnsense/mvc/app/controllers/OPNsense/Telegraf/forms/output.xml
@@ -347,7 +347,7 @@
         <id>output.opentelemetry_server</id>
         <label>OpenTelemetry Server</label>
         <type>text</type>
-        <help>Set the IP and port where metrics shoud be sent to, e.g. 192.168.0.1:4317.</help>
+        <help>For gRPC, set the address and port, e.g. 192.168.0.1:4317. For HTTP, use a full URL, e.g. https://collector.example.com/v1/metrics.</help>
     </field>
     <field>
         <id>output.opentelemetry_compression</id>
@@ -367,4 +367,16 @@
         <type>checkbox</type>
         <help>This will skip chain and host verification.</help>
     </field>
+    <field>
+        <id>output.opentelemetry_header_name</id>
+        <label>Custom Header Name</label>
+        <type>text</type>
+        <help>Name of an additional HTTP header to send with requests, e.g. Authorization.</help>
+    </field>
+    <field>
+        <id>output.opentelemetry_header_value</id>
+        <label>Custom Header Value</label>
+        <type>text</type>
+        <help>Value for the custom header, e.g. Bearer your-token-here.</help>
+    </field>
 </form>
diff --git a/net-mgmt/telegraf/src/opnsense/mvc/app/models/OPNsense/Telegraf/Output.xml b/net-mgmt/telegraf/src/opnsense/mvc/app/models/OPNsense/Telegraf/Output.xml
index 8c3828957..47a6f3e37 100644
--- a/net-mgmt/telegraf/src/opnsense/mvc/app/models/OPNsense/Telegraf/Output.xml
+++ b/net-mgmt/telegraf/src/opnsense/mvc/app/models/OPNsense/Telegraf/Output.xml
@@ -1,7 +1,7 @@
 <model>
     <mount>//OPNsense/telegraf/output</mount>
     <description>Telegraf outputs configuration</description>
-    <version>1.4.6</version>
+    <version>1.4.7</version>
     <items>
         <influx_enable type="BooleanField">
             <Default>0</Default>
@@ -204,5 +204,11 @@
                 <none>none</none>
             </OptionValues>
         </opentelemetry_compression>
+        <opentelemetry_header_name type="TextField">
+            <Required>N</Required>
+        </opentelemetry_header_name>
+        <opentelemetry_header_value type="TextField">
+            <Required>N</Required>
+        </opentelemetry_header_value>
     </items>
 </model>
diff --git a/net-mgmt/telegraf/src/opnsense/service/templates/OPNsense/Telegraf/telegraf.conf b/net-mgmt/telegraf/src/opnsense/service/templates/OPNsense/Telegraf/telegraf.conf
index acc65c904..bd11ec9d7 100644
--- a/net-mgmt/telegraf/src/opnsense/service/templates/OPNsense/Telegraf/telegraf.conf
+++ b/net-mgmt/telegraf/src/opnsense/service/templates/OPNsense/Telegraf/telegraf.conf
@@ -143,7 +143,7 @@
 {% if helpers.exists('OPNsense.telegraf.output.opentelemetry_enable') and OPNsense.telegraf.output.opentelemetry_enable == '1' %}
 [[outputs.opentelemetry]]
 {%   if helpers.exists('OPNsense.telegraf.output.opentelemetry_server') and OPNsense.telegraf.output.opentelemetry_server != '' %}
-  service_address = {{ OPNsense.telegraf.output.opentelemetry_server }}
+  service_address = "{{ OPNsense.telegraf.output.opentelemetry_server }}"
 {%   endif %}
 {%   if helpers.exists('OPNsense.telegraf.output.opentelemetry_timeout') and OPNsense.telegraf.output.opentelemetry_timeout != '' %}
   timeout = "{{ OPNsense.telegraf.output.opentelemetry_timeout }}s"
@@ -155,7 +155,11 @@
 {%   endif %}
 {%   if helpers.exists('OPNsense.telegraf.output.opentelemetry_compression') and OPNsense.telegraf.output.opentelemetry_compression != '' %}
   compression = "{{ OPNsense.telegraf.output.opentelemetry_compression }}"
-{%   endif %}
+{% endif %}
+{%   if helpers.exists('OPNsense.telegraf.output.opentelemetry_header_name') and OPNsense.telegraf.output.opentelemetry_header_name != '' %}
+[outputs.opentelemetry.headers]
+  "{{ OPNsense.telegraf.output.opentelemetry_header_name }}" = "{{ OPNsense.telegraf.output.opentelemetry_header_value }}"
+{% endif %}
 {% endif %}
 
 {% if helpers.exists('OPNsense.telegraf.output.graphite_enable') and OPNsense.telegraf.output.graphite_enable == '1' %}