diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fe772b3..e0bf28f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,13 +9,13 @@ jobs:
     strategy:
       matrix:
         operating-system: ['ubuntu-latest']
-        php-versions: ['7.4', '8.0', '8.1', '8.2', '8.3']
+        php-versions: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
 
-    continue-on-error: ${{ matrix.php-versions == '8.3' }}
+    continue-on-error: ${{ matrix.php-versions == '8.4' }}
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -27,11 +27,11 @@ jobs:
 
       - name: Install Composer dependencies (PHP < 8.1)
         if: ${{ matrix.php-versions != '8.3' }}
-        uses: "ramsey/composer-install@v1"
+        uses: "ramsey/composer-install@v3"
 
       - name: Install Composer dependencies - ignore-platform-reqs (PHP 8.1)
         if: ${{ matrix.php-versions == '8.3' }}
-        uses: "ramsey/composer-install@v1"
+        uses: "ramsey/composer-install@v3"
         with:
           composer-options: --ignore-platform-reqs
 
diff --git a/.github/workflows/psalm.yml b/.github/workflows/psalm.yml
index 3c4efea..8757d7f 100644
--- a/.github/workflows/psalm.yml
+++ b/.github/workflows/psalm.yml
@@ -9,10 +9,10 @@ jobs:
     strategy:
       matrix:
         operating-system: ['ubuntu-latest']
-        php-versions: ['8.1']
+        php-versions: ['8.3']
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -22,7 +22,7 @@ jobs:
           coverage: none
 
       - name: Install Composer dependencies
-        uses: "ramsey/composer-install@v1"
+        uses: "ramsey/composer-install@v3"
         with:
           composer-options: --no-dev
 
diff --git a/src/CSPBuilder.php b/src/CSPBuilder.php
index 83ab9b8..544121d 100644
--- a/src/CSPBuilder.php
+++ b/src/CSPBuilder.php
@@ -289,8 +289,10 @@ public function addSource(string $directive, string $path): self
         if (!isset($this->policies[$directive]['allow'])) {
             $this->policies[$directive]['allow'] = [];
         }
-        if (!in_array($path, $this->policies[$directive]['allow'], true)) {
-            $this->policies[$directive]['allow'][] = $path;
+        if (is_array($this->policies[$directive]['allow'])) {
+            if (!in_array($path, $this->policies[$directive]['allow'], true)) {
+                $this->policies[$directive]['allow'][] = $path;
+            }
         }
         return $this;
     }
@@ -1268,6 +1270,7 @@ protected function enc(string $piece, string $type = 'default'): string
      * Is this user currently connected over HTTPS?
      *
      * @return bool
+     * @psalm-suppress RiskyTruthyFalsyComparison
      */
     protected function isHTTPSConnection(): bool
     {