diff --git a/src/details_window.py b/src/details_window.py
index df56f0f..57ad67e 100644
--- a/src/details_window.py
+++ b/src/details_window.py
@@ -18,6 +18,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 import os
+import shlex
 from time import time
 
 from gi.repository import Adw, Gio, GLib, Gtk
@@ -66,7 +67,11 @@ class DetailsWindow(Adw.Window):
             self.name.set_text(self.game.name)
             if self.game.developer:
                 self.developer.set_text(self.game.developer)
-            self.executable.set_text(" ".join(self.game.executable))
+            self.executable.set_text(
+                self.game.executable
+                if isinstance(self.game.executable, str)
+                else shlex.join(self.game.executable)
+            )
             self.apply_button.set_label(_("Apply"))
 
             self.game_cover.new_cover(self.game.get_cover_path())
@@ -131,7 +136,6 @@ class DetailsWindow(Adw.Window):
         final_name = self.name.get_text()
         final_developer = self.developer.get_text()
         final_executable = self.executable.get_text()
-        final_executable_split = final_executable.split()
 
         if not self.game:
             if final_name == "":
@@ -183,7 +187,7 @@ class DetailsWindow(Adw.Window):
 
         self.game.name = final_name
         self.game.developer = final_developer or None
-        self.game.executable = final_executable_split
+        self.game.executable = final_executable
 
         if self.game.game_id in self.win.game_covers.keys():
             self.win.game_covers[self.game.game_id].animation = None
diff --git a/src/game.py b/src/game.py
index 8f0a13e..8067e95 100644
--- a/src/game.py
+++ b/src/game.py
@@ -65,6 +65,7 @@ class Game(Gtk.Box):
 
         self.win = shared.win
         self.app = self.win.get_application()
+        self.version = shared.spec_version
 
         self.update_values(data)
 
@@ -141,6 +142,7 @@ class Game(Gtk.Box):
             "developer",
             "removed",
             "blacklisted",
+            "version",
         )
 
         # TODO: remove for 2.0
@@ -179,19 +181,17 @@ class Game(Gtk.Box):
         self.last_played = int(time())
         self.save()
 
-        args = " ".join(
-            [
-                "flatpak-spawn",
-                "--host",
-                "/bin/sh",
-                "-c",
-                shlex.quote(" ".join(self.executable)),
-            ]
-            if os.getenv("FLATPAK_ID") == "hu.kramo.Cartridges"
-            else self.executable
+        string = (
+            self.executable
+            if isinstance(self.executable, str)
+            else shlex.join(self.executable)
         )
 
-        print(args)
+        args = (
+            "flatpak-spawn --host /bin/sh -c " + shlex.quote(string)  # Flatpak
+            if os.getenv("FLATPAK_ID") == "hu.kramo.Cartridges"
+            else string  # Others
+        )
 
         subprocess.Popen(
             args,
diff --git a/src/shared.py b/src/shared.py
index a40bef6..9cf54d5 100644
--- a/src/shared.py
+++ b/src/shared.py
@@ -52,3 +52,4 @@ image_size = (200 * scale_factor, 300 * scale_factor)
 # pylint: disable=invalid-name
 win = None
 importer = None
+spec_version = 1.5  # The version of the game_id.json spec
diff --git a/src/window.py b/src/window.py
index 2de6c5b..3c99464 100644
--- a/src/window.py
+++ b/src/window.py
@@ -100,6 +100,9 @@ class CartridgesWindow(Adw.ApplicationWindow):
                 games[data["game_id"]] = data
 
         for game_id, game in games.items():
+            if (version := game.get("version")) and version > shared.spec_version:
+                continue
+
             if game.get("removed"):
                 for path in (
                     shared.games_dir / f"{game_id}.json",