diff --git a/build/docker_install.sh b/build/docker_install.sh
index add8adbe..14aabcd5 100644
--- a/build/docker_install.sh
+++ b/build/docker_install.sh
@@ -17,5 +17,4 @@ chmod +x /usr/local/bin/phpunit
 docker-php-ext-configure gd --enable-gd-native-ttf --with-jpeg-dir=/usr/lib/x86_64-linux-gnu --with-png-dir=/usr/lib/x86_64-linux-gnu --with-freetype-dir=/usr/lib/x86_64-linux-gnu
 docker-php-ext-install gd
 docker-php-ext-install mcrypt
-docker-php-ext-install mbstring
 docker-php-ext-install zip
\ No newline at end of file