diff --git a/Dockerfile b/Dockerfile
index eb2e0b9..0a97734 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,10 @@
-FROM petzi/pre-commit:1.15.2-7
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends \
-    php-codesniffer \
-    && rm -rf /var/lib/apt/lists/*
+FROM petzi/pre-commit:1.15.2-9
+RUN apk add --no-cache \
+    php7-pear \
+    php7-openssl \
+    php7-simplexml \
+    php7-tokenizer \
+    php7-xmlwriter
+RUN pear channel-update pear.php.net
+RUN pear install --onlyreqdeps PHP_CodeSniffer
 COPY .pre-commit-config.yaml /