diff --git a/Dockerfile b/Dockerfile
index 7b82d801..d60241d7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -24,7 +24,7 @@ RUN set -eux; \
     pecl install -o -f redis; \
     docker-php-ext-enable redis; \
     docker-php-ext-install sockets ldap xsl zip pdo pdo_pgsql pdo_mysql sysvsem opcache \
-        bz2 mbstring pcntl; \
+        bz2 pcntl; \
     runDeps="$( \
         scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
             | tr ',' '\n' \