diff --git a/.github/workflows/blackbox.yml b/.github/workflows/blackbox.yml
index 2944b233..024edd07 100644
--- a/.github/workflows/blackbox.yml
+++ b/.github/workflows/blackbox.yml
@@ -22,7 +22,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           coverage: none
 
       - name: Install dependencies
diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 4bd07bf4..a9564c3d 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -20,7 +20,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           coverage: none
 
       - name: Install dependencies
@@ -34,10 +34,10 @@ jobs:
       fail-fast: false
       matrix:
         php:
-          - "7.4"
           - "8.0"
           - "8.1"
           - "8.2"
+          - "8.3"
     name: PHPStan on PHP ${{ matrix.php }}
     steps:
       - name: Checkout code
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index baafb6ad..8e33fae5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -9,7 +9,7 @@ jobs:
       fail-fast: true
       matrix:
         os: [ ubuntu-latest ]
-        php: [ 7.4, 8.0, 8.1, 8.2 ]
+        php: [ 8.0, 8.1, 8.2, 8.3 ]
         dependency-version: [ prefer-lowest, prefer-stable ]
         redis-version: [ 5, 6, 7 ]
 
diff --git a/php-fpm/Dockerfile b/php-fpm/Dockerfile
index f0d50190..5cc69b6a 100644
--- a/php-fpm/Dockerfile
+++ b/php-fpm/Dockerfile
@@ -1,4 +1,4 @@
-FROM php:8.1-fpm
+FROM php:8.2-fpm
 
 RUN pecl install redis && docker-php-ext-enable redis
 RUN pecl install apcu && docker-php-ext-enable apcu
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index 98ee73ea..b160865c 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -40,7 +40,7 @@ private function renderSample(MetricFamilySamples $metric, Sample $sample): stri
     {
         $labelNames = $metric->getLabelNames();
         if ($metric->hasLabelNames() || $sample->hasLabelNames()) {
-            $escapedLabels = $this->escapeAllLabels($labelNames, $sample);
+            $escapedLabels = $this->escapeAllLabels($metric, $labelNames, $sample);
             return $sample->getName() . '{' . implode(',', $escapedLabels) . '} ' . $sample->getValue();
         }
         return $sample->getName() . ' ' . $sample->getValue();
@@ -56,19 +56,20 @@ private function escapeLabelValue(string $v): string
     }
 
     /**
+     * @param MetricFamilySamples $metric
      * @param string[] $labelNames
      * @param Sample $sample
      *
      * @return string[]
      */
-    private function escapeAllLabels(array $labelNames, Sample $sample): array
+    private function escapeAllLabels(MetricFamilySamples $metric, array $labelNames, Sample $sample): array
     {
         $escapedLabels = [];
 
         $labels = array_combine(array_merge($labelNames, $sample->getLabelNames()), $sample->getLabelValues());
 
         if ($labels === false) {
-            throw new RuntimeException('Unable to combine labels.');
+            throw new RuntimeException('Unable to combine labels for metric named ' . $metric->getName());
         }
 
         foreach ($labels as $labelName => $labelValue) {