diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -3374,6 +3374,8 @@ def parsebundletype(repo, spec):
 
     if version is None:
         version = '01'
+        if 'generaldelta' in repo.requirements:
+            version = '02'
     else:
         try:
             version = _bundleversionspecs[version]
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -1223,7 +1223,7 @@ def bundle(ui, repo, fname, dest=None, *
     specify a compression, a bundle version or both using a dash
     (comp-version). The available compression methods are: none, bzip2,
     and gzip (by default, bundles are compressed using bzip2). The
-    available format are: v1, v2 (default to v1).
+    available format are: v1, v2 (default to most suitable).
 
     The bundle file can then be transferred using conventional means
     and applied to another repository with the unbundle or pull