diff --git a/build/docker/ubuntu-bionic/Dockerfile b/build/docker/ubuntu-bionic/Dockerfile
index 3566199..a0ed317 100644
--- a/build/docker/ubuntu-bionic/Dockerfile
+++ b/build/docker/ubuntu-bionic/Dockerfile
@@ -217,6 +217,7 @@
       php \
       php-cli \
       php-dev \
+      php-json \
       php-pear \
       re2c \
       composer