diff --git a/.circleci/config.yml b/.circleci/config.yml
index 65777f63..2a9d78a9 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -12,13 +12,13 @@ default: &default-steps
 jobs:
   test-emacs-25:
     docker:
-      - image: silex/emacs:25
+      - image: silex/emacs:25.3
         entrypoint: bash
     <<: *default-steps
 
   test-emacs-26:
     docker:
-      - image: silex/emacs:26.0
+      - image: silex/emacs:26.2
         entrypoint: bash
     <<: *default-steps
 
diff --git a/.emacs/init.el b/.emacs/init.el
index 4266ebd3..9db27dfa 100644
--- a/.emacs/init.el
+++ b/.emacs/init.el
@@ -3,6 +3,8 @@
 ;;
 ;; Usage: emacs -q -l $project_root/emacs/init.el
 
+(setq coding-system-for-write 'utf-8)
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Set `user-emacs-directory' to avoid overwriting $HOME/.emacs.d
 ;; See also: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=15539#66