diff --git a/Dockerfile b/Dockerfile
index 881b364..08d44e4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,6 +19,7 @@ RUN apk add --no-cache \
       php7-sockets \
       php7-tokenizer \
       php7-xml \
+      php7-xmlreader \
       php7-xmlwriter \
       php7-zlib