diff --git a/programs/diagnostics/testdata/configs/include/xml/user-include.xml b/programs/diagnostics/testdata/configs/include/xml/user-include.xml
index 01dc5e2da19..b12b34a56bb 100644
--- a/programs/diagnostics/testdata/configs/include/xml/user-include.xml
+++ b/programs/diagnostics/testdata/configs/include/xml/user-include.xml
@@ -1,4 +1,3 @@
-<?xml version="1.0" ?>
 <clickhouse>
     <test_user>
         <networks>
diff --git a/programs/diagnostics/testdata/docker/custom.xml b/programs/diagnostics/testdata/docker/custom.xml
index 9ff4e541959..bc1051178ca 100644
--- a/programs/diagnostics/testdata/docker/custom.xml
+++ b/programs/diagnostics/testdata/docker/custom.xml
@@ -1,4 +1,3 @@
-<?xml version="1.0" ?>
 <clickhouse>
     <listen_host>::</listen_host>
     <listen_host>0.0.0.0</listen_host>
diff --git a/utils/clickhouse-diagnostics/README.md b/utils/clickhouse-diagnostics/README.md
index fcc1be2f244..7d53dfdb197 100644
--- a/utils/clickhouse-diagnostics/README.md
+++ b/utils/clickhouse-diagnostics/README.md
@@ -34,7 +34,6 @@ Uptime: **13 minutes and 51 seconds**
 #### ClickHouse configuration
 **result**
 ```XML
-<?xml version="1.0" encoding="utf-8"?>
 <clickhouse>
 	<logger>
 		<level>trace</level>