diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 0000000..bb742bd
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,55 @@
+version: 2
+jobs:
+  test-php73:
+    docker:
+      - image: circleci/php:7.3-cli
+      - image: postgres:alpine
+        environment:
+          POSTGRES_PASSWORD: root
+          POSTGRES_USER: root
+          POSTGRES_DB: test
+      - image: mysql:5
+        environment:
+          MYSQL_ROOT_PASSWORD: root
+          MYSQL_DATABASE: test
+
+    working_directory: ~/project
+    steps:
+      - checkout
+
+      - run:
+          name: Run tests
+          command: |
+            composer update -n --prefer-dist --prefer-lowest --no-suggest
+            php vendor/bin/phpunit
+
+  test-php74:
+    docker:
+      - image: circleci/php:7.4-cli
+      - image: postgres:alpine
+        environment:
+          POSTGRES_PASSWORD: root
+          POSTGRES_USER: root
+          POSTGRES_DB: test
+      - image: mysql:5
+        environment:
+          MYSQL_ROOT_PASSWORD: root
+          MYSQL_DATABASE: test
+
+    working_directory: ~/project
+    steps:
+      - checkout
+
+      - run:
+          name: Run tests
+          command: |
+            composer update -n --prefer-dist --no-suggest
+            php vendor/bin/phpunit
+
+
+workflows:
+  version: 2
+  test:
+    jobs:
+      - test-php73
+      - test-php74
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 930b80c..904f381 100644
--- a/composer.json
+++ b/composer.json
@@ -11,14 +11,15 @@
     ],
     "require": {
         "php": "^7.3",
-        "doctrine/dbal": "*",
-        "react/event-loop": "*"
+        "doctrine/dbal": "^2.5",
+        "react/event-loop": "^1"
     },
     "require-dev": {
+        "phpunit/phpunit": "7.5.17",
         "clue/block-react": "*",
-        "react/mysql": "*",
-        "clue/reactphp-sqlite": "*",
-        "voryx/pgasync": "*"
+        "react/mysql": "^0.5",
+        "clue/reactphp-sqlite": "^1",
+        "voryx/pgasync": "^2"
     },
     "suggest": {
         "react/mysql": "MySQL usage",