diff --git a/system-variables.md b/system-variables.md
index 79af0db79a694..e9b5002f3c595 100644
--- a/system-variables.md
+++ b/system-variables.md
@@ -5758,7 +5758,7 @@ SHOW WARNINGS;
 - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No
 - Type: String
 - Default value: ""
-- Optional value: a string with a length of up to 64 characters. Valid characters include digits `0-9`, letters `a-zA-Z`, underscores `_`, and hyphens `-`.
+- Optional value: a string with a length of up to 64 characters. Valid characters include digits `0-9`, letters `a-zA-Z`, underscores `_`, and hyphens `-`. Sinc v8.5.6, the value of this variable is case-insensitive. The system converts the input value to lowercase for storage and comparison.
 - This variable is an instance-level system variable. You can use it to control the service scope of each TiDB node under the [TiDB Distributed eXecution Framework (DXF)](/tidb-distributed-execution-framework.md). The DXF determines which TiDB nodes can be scheduled to execute distributed tasks based on the value of this variable. For specific rules, see [Task scheduling](/tidb-distributed-execution-framework.md#task-scheduling).
 
 ### tidb_session_alias <span class="version-mark">New in v7.4.0</span>