diff --git a/.circleci/config.yml b/.circleci/config.yml
index 2588646..4d1dae7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,7 +3,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: nemtrif/utf8cpp:3.1.3
+      - image: nemtrif/utf8cpp:4.0.0
     steps:
       - checkout
       - run: git submodule update --init --recursive --remote