diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index 2588d6d7b8..1a17572d14 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -418,7 +418,7 @@ make prefix=/usr/local/pgsql.new install
      </listitem>
      <listitem>
       <para>
-       Old cluster has replicated all the changes replicated to subscribers.
+       The old cluster has replicated all the changes to subscribers.
       </para>
      </listitem>
      <listitem>
diff --git a/src/backend/utils/adt/pg_upgrade_support.c b/src/backend/utils/adt/pg_upgrade_support.c
index c4b2980a8a..2914b2833e 100644
--- a/src/backend/utils/adt/pg_upgrade_support.c
+++ b/src/backend/utils/adt/pg_upgrade_support.c
@@ -12,9 +12,7 @@
 #include "postgres.h"
 
 #include "access/heapam_xlog.h"
-#include "access/rmgr.h"
 #include "access/xlog.h"
-#include "access/xlog_internal.h"
 #include "access/xlogutils.h"
 #include "catalog/binary_upgrade.h"
 #include "catalog/heap.h"
@@ -279,17 +277,13 @@ binary_upgrade_set_missing_value(PG_FUNCTION_ARGS)
  * This function is used to verify that there are no WAL records (except some
  * types) after confirmed_flush_lsn of logical slots, which means all the
  * changes were replicated to the subscriber. There is a possibility that some
- * WALs are inserted after logical waslenders exit, so such types would be
- * ignored.
+ * WALs are inserted during upgrade, so such types would be ignored.
  *
  * XLOG_CHECKPOINT_SHUTDOWN is ignored because it would be inserted after the
- * waslender exits. Moreover, the following types of records would be during
- * the pg_upgrade --check, so they are ignored too.
- *
- *             - XLOG_CHECKPOINT_ONLINE
- *             - XLOG_RUNNING_XACTS
- *             - XLOG_FPI_FOR_HINT
- *             - XLOG_HEAP2_PRUNE
+ * waslender exits. Moreover, the following types of records could be generated
+ * during the pg_upgrade --check, so they are ignored too:
+ * XLOG_CHECKPOINT_ONLINE, XLOG_RUNNING_XACTS, XLOG_FPI_FOR_HINT,
+ * XLOG_HEAP2_PRUNE, XLOG_PARAMETER_CHANGE.
  */
 Datum
 binary_upgrade_validate_wal_record_types_after_lsn(PG_FUNCTION_ARGS)
diff --git a/src/bin/pg_upgrade/check.c b/src/bin/pg_upgrade/check.c
index df1ce67fc0..37c75bd024 100644
--- a/src/bin/pg_upgrade/check.c
+++ b/src/bin/pg_upgrade/check.c
@@ -1399,8 +1399,8 @@ check_for_user_defined_encoding_conversions(ClusterInfo *cluster)
 /*
  * check_new_cluster_logical_replication_slots()
  *
- * Make sure there are no logical replication slots on the new cluster and that
- * the parameter settings necessary for creating slots are sufficient.
+ * Verify that there are no logical replication slots on the new cluster and
+ * that the parameter settings necessary for creating slots are sufficient.
  */
 static void
 check_new_cluster_logical_replication_slots(void)
@@ -1476,12 +1476,8 @@ check_new_cluster_logical_replication_slots(void)
 /*
  * check_old_cluster_for_valid_slots()
  *
- * Make sure logical replication slots can be migrated to new cluster.
- * Following points are checked:
- *
- *	- All logical replication slots are usable.
- *	- All logical replication slots consumed all WALs, except some acceptable
- *	  types.
+ * Verify that all the logical slots are usable and consumed all the WAL
+ * before shutdown.
  */
 static void
 check_old_cluster_for_valid_slots(bool live_check)
@@ -1521,8 +1517,8 @@ check_old_cluster_for_valid_slots(bool live_check)
 			}
 
 			/*
-			 * Do additional checks to ensure that all logical replication
-			 * slots have reached the current WAL position.
+			 * Do additional check to ensure that all logical replication slots
+			 * have consumed all the WAL before shutdown.
 			 *
 			 * Note: This can be satisfied only when the old cluster has been
 			 * shut down, so we skip this for live checks.