--- a/.emacs-my	Thu Jul 19 15:06:02 2018 +0300
+++ b/.emacs-my	Wed Jul 25 21:52:30 2018 +0300
@@ -3509,7 +3509,9 @@
 (add-to-list 'auto-mode-alist '("\.atom\\'" . nxml-mode))
 
 (my--eval-after-load nxml-mode
-  (define-key nxml-mode-map [C-return] 'nxml-complete))
+  (if (<= emacs-major-version 25)
+      (define-key nxml-mode-map [C-return] 'nxml-complete)
+    (define-key nxml-mode-map [C-return] 'completion-at-point))
 
 (defun my-nxml-pp ()
   "Pretty-print XML."