diff --git a/generator/docstrings.ml b/generator/docstrings.ml
index d7d00012b..3faaa57cf 100644
--- a/generator/docstrings.ml
+++ b/generator/docstrings.ml
@@ -36,10 +36,12 @@ let protocol_limit_warning =
   "Because of the message protocol, there is a transfer limit
 of somewhere between 2MB and 4MB.  See L<guestfs(3)/PROTOCOL LIMITS>."
 
-let deprecation_notice ?(prefix = "") =
+let deprecation_notice ?(prefix = "") ?(replace_underscores = false) =
   function
   | { deprecated_by = None } -> None
   | { deprecated_by = Some alt } ->
+    let alt =
+      if replace_underscores then replace_char alt '_' '-' else alt in
     let txt =
       sprintf "I<This function is deprecated.>
 In new code, use the L</%s%s> call instead.
diff --git a/generator/fish.ml b/generator/fish.ml
index e8ab91f4e..76377a24b 100644
--- a/generator/fish.ml
+++ b/generator/fish.ml
@@ -151,7 +151,7 @@ Guestfish will prompt for these separately."
 
       let warnings =
         warnings ^
-          match deprecation_notice f with
+          match deprecation_notice ~replace_underscores:true f with
           | None -> ""
           | Some txt -> "\n\n" ^ txt in
 
@@ -891,7 +891,7 @@ Guestfish will prompt for these separately.\n\n";
       if f.protocol_limit_warning then
         pr "%s\n\n" protocol_limit_warning;
 
-      match deprecation_notice f with
+      match deprecation_notice ~replace_underscores:true f with
       | None -> ()
       | Some txt -> pr "%s\n\n" txt
   ) all_functions_sorted