diff --git a/.github/workflows/push.yml b/.github/workflows/push.yml
index 547e71e..7c9303f 100644
--- a/.github/workflows/push.yml
+++ b/.github/workflows/push.yml
@@ -9,6 +9,10 @@ env:
 jobs:
   tests:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        symfonyVersion: ["5.4.*", "6.1.*"]
     steps:
       -
         name: 'Check out the repo'
@@ -19,7 +23,7 @@ jobs:
         run: 'docker login --username "$DOCKERHUB_USER" --password "$DOCKERHUB_TOKEN"'
       -
         name: 'Build image'
-        run: 'docker build -t $APP_IMAGE .'
+        run: 'docker build --build-arg SYMFONY_REQUIRE=${{ matrix.symfonyVersion }} -t $APP_IMAGE .'
       -
         name: 'Run tests'
         run: 'docker run ${{env.APP_IMAGE}} composer ci'
diff --git a/Dockerfile b/Dockerfile
index 4fcb3ae..e1a208e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,6 +3,8 @@ ARG phpversion=8
 FROM php:${phpversion}-cli
 
 ARG COMPOSER_FLAGS="--prefer-dist --no-interaction"
+ARG SYMFONY_REQUIRE=6.*
+
 ARG DEBIAN_FRONTEND=noninteractive
 ENV COMPOSER_ALLOW_SUPERUSER 1
 ENV COMPOSER_PROCESS_TIMEOUT 3600
@@ -19,6 +21,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 	&& chmod +x /tmp/composer-install.sh \
 	&& /tmp/composer-install.sh
 
+# To enable SYMFONY_REQUIRE
+RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin/ --filename=composer \
+ && composer global config allow-plugins.symfony/flex true \
+ && composer global require --no-progress --no-scripts --no-plugins symfony/flex
+
 ## Composer - deps always cached unless changed
 # First copy only composer files
 COPY composer.* /code/
diff --git a/composer.json b/composer.json
index 7840877..925c9b4 100644
--- a/composer.json
+++ b/composer.json
@@ -6,10 +6,10 @@
         "PHP": "^7.4|^8.0",
         "ext-json": "*",
         "keboola/php-temp": "^2.0",
-        "phpunit/phpunit": "^9.0",
-        "symfony/filesystem": "^5.0",
-        "symfony/finder": "^5.0",
-        "symfony/process": "^5.0"
+        "phpunit/phpunit": "^9.5",
+        "symfony/filesystem": "^5.0|^6.0",
+        "symfony/finder": "^5.0|^6.0",
+        "symfony/process": "^5.0|^6.0"
     },
     "require-dev": {
         "php-parallel-lint/php-parallel-lint": "^1.3",
@@ -35,6 +35,7 @@
     },
     "config": {
         "sort-packages": true,
+        "lock": false,
         "optimize-autoloader": true,
         "allow-plugins": {
             "dealerdirect/phpcodesniffer-composer-installer": true