diff --git a/Dockerfile b/Dockerfile
index 0a54970..d1ba170 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,13 +1,13 @@
 # Inherit from Heroku's stack
-FROM heroku/cedar:14
+FROM heroku/heroku:18-build
 
 # Internally, we arbitrarily use port 3000
 ENV PORT 3000
 
 # Which versions?
-ENV PHP_VERSION 5.6.15
-ENV HTTPD_VERSION 2.4.17
-ENV NGINX_VERSION 1.8.0
+ENV PHP_VERSION 7.3.7
+ENV HTTPD_VERSION 2.4.39
+ENV NGINX_VERSION 1.16.0
 
 # Create some needed directories
 RUN mkdir -p /app/.heroku/php /app/.profile.d
@@ -17,28 +17,28 @@ WORKDIR /app/user
 ENV PATH /app/.heroku/php/bin:/app/.heroku/php/sbin:$PATH
 
 # Install Apache
-RUN curl --silent --location https://lang-php.s3.amazonaws.com/dist-cedar-14-master/apache-$HTTPD_VERSION.tar.gz | tar xz -C /app/.heroku/php
+RUN curl --silent --location https://lang-php.s3.amazonaws.com/dist-heroku-18-develop/apache-$HTTPD_VERSION.tar.gz | tar xz -C /app/.heroku/php
 # Config
-RUN curl --silent --location https://raw.githubusercontent.com/heroku/heroku-buildpack-php/5a770b914549cf2a897cbbaf379eb5adf410d464/conf/apache2/httpd.conf.default > /app/.heroku/php/etc/apache2/httpd.conf
+RUN curl --silent --location https://raw.githubusercontent.com/heroku/heroku-buildpack-php/ded7e8a02e472387fb9cdb98e84b7f82d8eb3b91/conf/apache2/httpd.conf.default > /app/.heroku/php/etc/apache2/httpd.conf
 # FPM socket permissions workaround when run as root
 RUN echo "\n\
 Group root\n\
 " >> /app/.heroku/php/etc/apache2/httpd.conf
 
 # Install Nginx
-RUN curl --silent --location https://lang-php.s3.amazonaws.com/dist-cedar-14-master/nginx-$NGINX_VERSION.tar.gz | tar xz -C /app/.heroku/php
+RUN curl --silent --location https://lang-php.s3.amazonaws.com/dist-heroku-18-develop/nginx-$NGINX_VERSION.tar.gz | tar xz -C /app/.heroku/php
 # Config
-RUN curl --silent --location https://raw.githubusercontent.com/heroku/heroku-buildpack-php/5a770b914549cf2a897cbbaf379eb5adf410d464/conf/nginx/nginx.conf.default > /app/.heroku/php/etc/nginx/nginx.conf
+RUN curl --silent --location https://raw.githubusercontent.com/heroku/heroku-buildpack-php/ded7e8a02e472387fb9cdb98e84b7f82d8eb3b91/conf/nginx/nginx.conf.default > /app/.heroku/php/etc/nginx/nginx.conf
 # FPM socket permissions workaround when run as root
 RUN echo "\n\
 user nobody root;\n\
 " >> /app/.heroku/php/etc/nginx/nginx.conf
 
 # Install PHP
-RUN curl --silent --location https://lang-php.s3.amazonaws.com/dist-cedar-14-master/php-$PHP_VERSION.tar.gz | tar xz -C /app/.heroku/php
+RUN curl --silent --location https://lang-php.s3.amazonaws.com/dist-heroku-18-develop/php-$PHP_VERSION.tar.gz | tar xz -C /app/.heroku/php
 # Config
 RUN mkdir -p /app/.heroku/php/etc/php/conf.d
-RUN curl --silent --location https://raw.githubusercontent.com/heroku/heroku-buildpack-php/5a770b914549cf2a897cbbaf379eb5adf410d464/conf/php/php.ini > /app/.heroku/php/etc/php/php.ini
+RUN curl --silent --location https://raw.githubusercontent.com/heroku/heroku-buildpack-php/ded7e8a02e472387fb9cdb98e84b7f82d8eb3b91/conf/php/php.ini > /app/.heroku/php/etc/php/php.ini
 # Enable all optional exts
 RUN echo "\n\
 user_ini.cache_ttl = 30 \n\
@@ -65,7 +65,7 @@ extension=xsl.so\n\
 " >> /app/.heroku/php/etc/php/php.ini
 
 # Install Composer
-RUN curl --silent --location "https://lang-php.s3.amazonaws.com/dist-cedar-14-master/composer-1.0.0alpha11.tar.gz" | tar xz -C /app/.heroku/php
+RUN curl --silent --location "https://lang-php.s3.amazonaws.com/dist-heroku-18-develop/composer-1.8.6.tar.gz" | tar xz -C /app/.heroku/php
 
 # copy dep files first so Docker caches the install step if they don't change
 ONBUILD COPY composer.lock /app/user/
@@ -81,4 +81,4 @@ ONBUILD RUN cat composer.json | python -c 'import sys,json; sys.exit("post-insta
 
 # TODO: run "composer compile", like Heroku?
 
-# ENTRYPOINT ["/usr/bin/init.sh"]
\ No newline at end of file
+# ENTRYPOINT ["/usr/bin/init.sh"]