diff --git a/parinfer-rust-helper.el b/parinfer-rust-helper.el
index 197c4d8..6b736ed 100644
--- a/parinfer-rust-helper.el
+++ b/parinfer-rust-helper.el
@@ -79,15 +79,18 @@ library was downloaded."
 
 If SUPPORTED-VERSIONS is not compatible with CURRENT-VERSION,
 offer to download the LIB-NAME to LIBRARY-LOCATION."
-  (when (and current-version
-             (not (member-ignore-case
-                   current-version
-                   supported-versions))
-             (and
-              (not (parinfer-rust--test-p))
-              (yes-or-no-p parinfer-rust--outdated-version)))
-    (parinfer-rust--download-from-github (car supported-versions) library-location lib-name)
-    (message "A new version has been downloaded, you will need to reload Emacs for the changes to take effect.")))
+  (if (and current-version
+           (not (member-ignore-case
+                 current-version
+                 supported-versions))
+           (and
+            (not (parinfer-rust--test-p))
+            (yes-or-no-p parinfer-rust--outdated-version)))
+      (parinfer-rust--download-from-github (car supported-versions) library-location lib-name)
+    (message "A new version has been downloaded, you will need to reload Emacs for the changes to take effect.")
+    (and (string= "0.4.3" current-version)
+         (display-warning '(parinfer-rust-mode)
+                          "parinfer-rust-mode now relies on a fork of parinfer-rust and has dropped support for v0.4.3.\nPlease go to https://github.com/justinbarclay/parinfer-rust/discussions/9 to find out more."))))
 
 (defun parinfer-rust--download-from-github (parinfer-rust-version
                                             library-location