Update TODO reference for flag cleanup

RELNOTES: None
PiperOrigin-RevId: 258859323
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandEventHandler.java b/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandEventHandler.java
index 2292e9b..b62ba6f 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandEventHandler.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandEventHandler.java
@@ -108,7 +108,7 @@
 
     @Option(
         name = "isatty",
-        // TODO(b/123504199): Old name should be removed after 2020-01-01, or whenever is
+        // TODO(b/137881511): Old name should be removed after 2020-01-01, or whenever is
         // reasonable.
         oldName = "is_stderr_atty",
         defaultValue = "false",