diff --git a/app/Dockerfile b/app/Dockerfile
index ecd9254..80cd807 100644
--- a/app/Dockerfile
+++ b/app/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.16
+FROM alpine:3.17
 EXPOSE 9000/tcp
 
 ENV SCRIPT_ROOT=/opt/tt-rss
@@ -8,7 +8,7 @@ RUN apk add --no-cache dcron php81 php81-fpm php81-phar php81-sockets \
 	php81-mbstring php81-intl php81-xml php81-curl php81-simplexml \
 	php81-session php81-tokenizer php81-dom php81-fileinfo php81-ctype \
 	php81-json php81-iconv php81-pcntl php81-posix php81-zip php81-exif \
-	php81-openssl git postgresql-client sudo php81-pecl-xdebug rsync && \
+	php81-openssl git postgresql-client sudo php81-pecl-xdebug rsync tzdata && \
 	sed -i 's/\(memory_limit =\) 128M/\1 256M/' /etc/php81/php.ini && \
 	sed -i -e 's/^listen = 127.0.0.1:9000/listen = 9000/' \
 		-e 's/;\(clear_env\) = .*/\1 = no/i' \
diff --git a/web-nginx/Dockerfile b/web-nginx/Dockerfile
index 50d976b..b92f8f2 100644
--- a/web-nginx/Dockerfile
+++ b/web-nginx/Dockerfile
@@ -2,4 +2,14 @@ FROM nginx:alpine
 
 HEALTHCHECK CMD curl --fail http://localhost/tt-rss/index.php || exit 1
 
-COPY nginx.conf /etc/nginx/nginx.conf
+COPY nginx.conf /etc/nginx/templates/nginx.conf.template
+
+# By default, nginx will send the php requests to "app" server, but this server
+# name can be overridden at runtime by passing an APP_UPSTREAM env var
+ENV APP_UPSTREAM=${APP_UPSTREAM:-app}
+
+# It's necessary to set the following NGINX_ENVSUBST_OUTPUT_DIR env var to tell
+# nginx to replace the env vars of /etc/nginx/templates/nginx.conf.template
+# and put the result in /etc/nginx/nginx.conf (instead of /etc/nginx/conf.d/nginx.conf)
+# See https://github.com/docker-library/docs/tree/master/nginx#using-environment-variables-in-nginx-configuration-new-in-119
+ENV NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx
diff --git a/web-nginx/nginx.conf b/web-nginx/nginx.conf
index 40b11f7..7616169 100644
--- a/web-nginx/nginx.conf
+++ b/web-nginx/nginx.conf
@@ -17,7 +17,7 @@ http {
 	index index.php;
 
 	upstream app {
-		server app:9000;
+		server ${APP_UPSTREAM}:9000;
 	}
 
 	server {