Export legacy converted beatmaps as .osz and non-converted beatmaps as .osz2

osu.Game/Beatmaps/BeatmapImporter.cs

@@ -29,7 +29,7 @@ namespace osu.Game.Beatmaps
     /// </summary>
     public class BeatmapImporter : RealmArchiveModelImporter<BeatmapSetInfo>
     {
-        public override IEnumerable<string> HandledExtensions => new[] { ".osz" };
+        public override IEnumerable<string> HandledExtensions => new[] { ".osz", ".osz2" };
 
         protected override string[] HashableFileTypes => new[] { ".osu" };
 
@@ -145,7 +145,7 @@ namespace osu.Game.Beatmaps
             }
         }
 
-        protected override bool ShouldDeleteArchive(string path) => Path.GetExtension(path).ToLowerInvariant() == ".osz";
+        protected override bool ShouldDeleteArchive(string path) => HandledExtensions.Contains(Path.GetExtension(path).ToLowerInvariant());
 
         protected override void Populate(BeatmapSetInfo beatmapSet, ArchiveReader? archive, Realm realm, CancellationToken cancellationToken = default)
         {

osu.Game/Beatmaps/BeatmapManager.cs

@@ -44,7 +44,9 @@ namespace osu.Game.Beatmaps
 
         private readonly WorkingBeatmapCache workingBeatmapCache;
 
-        private readonly LegacyBeatmapExporter beatmapExporter;
+        private readonly BeatmapExporter beatmapExporter;
+
+        private readonly LegacyBeatmapExporter legacyBeatmapExporter;
 
         public ProcessBeatmapDelegate? ProcessBeatmap { private get; set; }
 
@@ -81,7 +83,12 @@ namespace osu.Game.Beatmaps
 
             workingBeatmapCache = CreateWorkingBeatmapCache(audioManager, gameResources, userResources, defaultBeatmap, host);
 
-            beatmapExporter = new LegacyBeatmapExporter(storage)
+            beatmapExporter = new BeatmapExporter(storage)
+            {
+                PostNotification = obj => PostNotification?.Invoke(obj)
+            };
+
+            legacyBeatmapExporter = new LegacyBeatmapExporter(storage)
             {
                 PostNotification = obj => PostNotification?.Invoke(obj)
             };
@@ -443,7 +450,7 @@ namespace osu.Game.Beatmaps
                 });
             }
 
-            return beatmapExporter.ExportAsync(new RealmLiveUnmanaged<BeatmapSetInfo>(clone));
+            return legacyBeatmapExporter.ExportAsync(new RealmLiveUnmanaged<BeatmapSetInfo>(clone));
         }
 
         private void convertAndEncodeLegacyBeatmap(IBeatmap beatmapContent, ISkin beatmapSkin, Stream stream)

osu.Game/Database/BeatmapExporter.cs

@@ -0,0 +1,18 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Platform;
+using osu.Game.Beatmaps;
+
+namespace osu.Game.Database
+{
+    public class BeatmapExporter : LegacyArchiveExporter<BeatmapSetInfo>
+    {
+        public BeatmapExporter(Storage storage)
+            : base(storage)
+        {
+        }
+
+        protected override string FileExtension => @".osz2";
+    }
+}