diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index d0686ef..6e54095 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2014,6 +2014,25 @@
   let files = readdir(dir, '1', #{sort: 'icase'})
   call assert_equal(default->sort('i'), files, 'sort by ignoring case')
 
+  " 4) collation
+  let collate = v:collate
+  lang collate C
+  let files = readdir(dir, 1, #{sort: 'collate'})
+  call assert_equal(default->sort(), files, 'sort by C collation')
+  exe "lang collate" collate
+
+  " 5) Errors
+  call assert_fails('call readdir(dir, 1, 1)', 'E715')
+  call assert_fails('call readdir(dir, 1, #{sorta: 1})')
+  call assert_fails('call readdirex(dir, 1, #{sorta: 1})')
+
+  " 6) ignore other values in dict
+  let files = readdir(dir, '1', #{sort: 'c'})
+  call assert_equal(default, files, 'sort using default2')
+
+  " Cleanup
+  exe "lang collate" collate
+
   eval dir->delete('rf')
 endfunc
 
diff --git a/src/version.c b/src/version.c
index a5c6de5..509ef22 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    995,
+/**/
     994,
 /**/
     993,