diff --git a/src/testdir/test_man.vim b/src/testdir/test_man.vim
index 9de8cb4..083b1ae 100644
--- a/src/testdir/test_man.vim
+++ b/src/testdir/test_man.vim
@@ -1,3 +1,5 @@
+" Test specifically for the Man filetype plugin.
+
 runtime ftplugin/man.vim
 
 func Test_g_ft_man_open_mode()
@@ -111,3 +113,21 @@
   %bw!
   set foldcolumn& number&
 endfunc
+
+" Check that the unnamed register is not overwritten.
+func Test_keep_unnamed_register()
+  %bw!
+
+  let @" = '---'
+
+  let wincnt = winnr('$')
+  Man vim
+  if wincnt == winnr('$')
+    " Vim manual page cannot be found.
+    return
+  endif
+
+  call assert_equal('---', @")
+
+  %bw!
+endfunc
diff --git a/src/version.c b/src/version.c
index d4250e5..5659e92 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    568,
+/**/
     567,
 /**/
     566,