diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 64b8f838be..f5f111495b 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -473,3 +473,17 @@ both, older and future versions of QEMU.
 The ``blacklist`` config file option has been renamed to ``block-rpcs``
 (to be in sync with the renaming of the corresponding command line
 option).
+
+Migration
+---------
+
+``fd:`` URI when used for file migration (since 9.1)
+''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+The ``fd:`` URI can currently provide a file descriptor that
+references either a socket or a plain file. These are two different
+types of migration. In order to reduce ambiguity, the ``fd:`` URI
+usage of providing a file descriptor to a plain file has been
+deprecated in favor of explicitly using the ``file:`` URI with the
+file descriptor being passed as an ``fdset``. Refer to the ``add-fd``
+command documentation for details on the ``fdset`` usage.
diff --git a/migration/fd.c b/migration/fd.c
index 449adaa2de..aab5189eac 100644
--- a/migration/fd.c
+++ b/migration/fd.c
@@ -20,6 +20,8 @@
 #include "file.h"
 #include "migration.h"
 #include "monitor/monitor.h"
+#include "qemu/error-report.h"
+#include "qemu/sockets.h"
 #include "io/channel-util.h"
 #include "trace.h"
 
@@ -32,6 +34,11 @@ void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **
         return;
     }
 
+    if (!fd_is_socket(fd)) {
+        warn_report("fd: migration to a file is deprecated."
+                    " Use file: instead.");
+    }
+
     trace_migration_fd_outgoing(fd);
     ioc = qio_channel_new_fd(fd, errp);
     if (!ioc) {
@@ -61,6 +68,11 @@ void fd_start_incoming_migration(const char *fdname, Error **errp)
         return;
     }
 
+    if (!fd_is_socket(fd)) {
+        warn_report("fd: migration to a file is deprecated."
+                    " Use file: instead.");
+    }
+
     trace_migration_fd_incoming(fd);
 
     ioc = qio_channel_new_fd(fd, errp);