diff --git a/asdf-encodings.asd b/asdf-encodings.asd
index 1d23ee6836434f8b20329beb2bfd9bde858034a1..fc9c26bfe552864426f80f81a1d41c772da01ce2 100644
--- a/asdf-encodings.asd
+++ b/asdf-encodings.asd
@@ -1,7 +1,12 @@
 ;;; -*- Mode: Lisp ; Base: 10 ; Syntax: ANSI-Common-Lisp -*-
-(defsystem :asdf-encodings
+
+;; Ensure upgrade, so #+asdf-unicode below has better chances of working.
+(asdf:oos 'asdf:load-op :asdf)
+
+(asdf:defsystem :asdf-encodings
   :description "Portable interface to character encodings and your implementation's external-format"
   :depends-on ((:version "asdf" "2.20.18"))
+  #+asdf-unicode #+asdf-unicode ;; disabled in implementations with no unicode support.
   :components
   ((:file "pkgdcl")
    (:file "encodings" :depends-on ("pkgdcl"))
@@ -9,7 +14,6 @@
    (:file "asdf-support" :depends-on ("pkgdcl"))
    (:file "initialization" :depends-on ("pkgdcl"))))
 
-
 (defmethod perform ((op test-op) (system (eql (find-system :asdf-encodings))))
   (asdf:load-system :asdf-encodings-test)
   (funcall (asdf:find-symbol* :test-suite :asdf-encodings-test)))