Display a dialog box message saying that there's no update when manually checking

ftl/qt/qt-misc.ftl

@@ -3,6 +3,7 @@ qt-misc-addons = Add-ons
 qt-misc-all-cards-notes-and-media-for = All cards, notes, and media for this profile will be deleted. Are you sure?
 qt-misc-all-cards-notes-and-media-for2 = All cards, notes, and media for the profile "{ $name }" will be deleted. Are you sure?
 qt-misc-anki-updatedanki-has-been-released = <h1>Anki Updated</h1>Anki { $val } has been released.<br><br>
+qt-misc-no-update-available = You're up to date!<br><br>Anki { $val } is currently the newest version available.
 qt-misc-automatic-syncing-and-backups-have-been = Backup successfully restored. Automatic syncing and backups have been disabled for now. To enable them again, close the profile or restart Anki.
 qt-misc-back-side-only = Back Side Only
 qt-misc-backing-up = Backing Up...

qt/aqt/main.py

@@ -1335,7 +1335,7 @@ title="{}" {}>{}</button>""".format(
     def onCheckForUpdates(self) -> None:
         from aqt.update import check_for_update
 
-        check_for_update()
+        check_for_update(notify_if_no_update=True)
 
     # legacy
 

qt/aqt/update.py

@@ -15,10 +15,10 @@ from aqt.package import (
     update_and_restart as _update_and_restart,
 )
 from aqt.qt import *
-from aqt.utils import openLink, show_warning, showText, tr
+from aqt.utils import openLink, show_info, show_warning, showText, tr
 
 
-def check_for_update() -> None:
+def check_for_update(notify_if_no_update: bool = False) -> None:
     from aqt import mw
 
     def do_check(_col: Collection) -> CheckForUpdateResponse:
@@ -54,6 +54,11 @@ def check_for_update() -> None:
         if ver := resp.new_version:
             if mw.pm.meta.get("suppressUpdate", None) != ver:
                 prompt_to_update(mw, ver)
+        elif notify_if_no_update:
+            show_info(
+                tr.qt_misc_no_update_available(val=aqt.appVersion),
+                textFormat=Qt.TextFormat.RichText,
+            )
 
     def on_fail(exc: Exception) -> None:
         print(f"update check failed: {exc}")