diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f007759..1a14194 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -18,7 +18,7 @@ jobs:
     strategy:
       matrix:
         php-version: ['7.4', '8.0', '8.1', '8.2']
-        rts-version: ['1.4.13', '1.6.19', '1.8.10']
+        rts-version: ['1.4.13', '1.6.19', '1.8.12']
     steps:
       - uses: actions/checkout@v3
       - uses: adambirds/docker-compose-action@v1.3.0
diff --git a/Dockerfile b/Dockerfile
index 4461bc2..7c81514 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -14,8 +14,9 @@ RUN apt-get -y upgrade && \
     apt-get update && \
     apt-get install -yqq zip git wget
 
-RUN pecl install igbinary redis ${XDEBUG_PACKAGE} && \
-    docker-php-ext-enable igbinary redis xdebug
+ADD https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions /usr/local/bin/
+RUN chmod +x /usr/local/bin/install-php-extensions && \
+    install-php-extensions igbinary redis xdebug
 
 RUN wget https://github.com/composer/composer/releases/download/${COMPOSER_VERSION}/composer.phar -q && \
     mv composer.phar /usr/bin/composer && \
diff --git a/docker-compose.yml b/docker-compose.yml
index 365e605..415c881 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -6,10 +6,10 @@ services:
       dockerfile: Dockerfile
       context: .
       args:
-        PHP_VERSION: ${PHP_VERSION}
+        PHP_VERSION: ${PHP_VERSION-7.4}
     entrypoint: sleep infinity
     volumes:
       - .:/app
       - ./docker/xdebug.ini:/usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
   php-rts-redis:
-    image: redislabs/redistimeseries:${RTS_VERSION}
+    image: redislabs/redistimeseries:${RTS_VERSION-1.4.13}
diff --git a/run_ci.sh b/run_ci.sh
index 31da221..903dac8 100755
--- a/run_ci.sh
+++ b/run_ci.sh
@@ -4,4 +4,4 @@ set -e
 
 composer install --no-progress --prefer-dist --optimize-autoloader
 ./vendor/bin/phpunit --coverage-text
-#./vendor/bin/psalm
+./vendor/bin/psalm
diff --git a/src/Client/RedisClient.php b/src/Client/RedisClient.php
index e46185d..18d9481 100644
--- a/src/Client/RedisClient.php
+++ b/src/Client/RedisClient.php
@@ -90,8 +90,8 @@ public function executeCommand(array $params)
     private function authenticate(?string $username, ?string $password): void
     {
         try {
-            if ($password) {
-                if ($username) {
+            if ($password !== null) {
+                if ($username !== null) {
                     // Calling auth() with an array throws a TypeError in some cases
                     /**
                      * @noinspection PhpMethodParametersCountMismatchInspection
@@ -104,13 +104,16 @@ private function authenticate(?string $username, ?string $password): void
                 }
                 if ($result === false) {
                     throw new RedisAuthenticationException(sprintf(
-                        'Failure authenticating user %s', $username ?: 'default'
+                        'Failure authenticating user %s',
+                        $username === null ? 'default' : $username
                     ));
                 }
             }
         } /** @noinspection PhpRedundantCatchClauseInspection */ catch (RedisException $e) {
             throw new RedisAuthenticationException(sprintf(
-                'Failure authenticating user %s: %s', $username ?: 'default', $e->getMessage()
+                'Failure authenticating user %s: %s',
+                $username === null ? 'default' : $username,
+                $e->getMessage()
             ));
         }
     }