diff --git a/Dockerfile b/Dockerfile
index 8596fcb..fa83f9b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,6 +15,7 @@ RUN \
 	php7-dom \
 	php7-gd \
 	php7-intl \
+	php7-mbstring \
 	php7-opcache \
 	php7-openssl \
 	php7-pdo_sqlite \