diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3ee0ac3..fe38d1c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: 8.2
+          php-version: 8.3
           extensions: imagick
           coverage: xdebug
           tools: phpstan
diff --git a/composer.json b/composer.json
index 9135d16..a318f3e 100644
--- a/composer.json
+++ b/composer.json
@@ -16,10 +16,10 @@
     "nohn/analogmeterreader": "^1.2",
     "php": ">=7.4",
     "ext-imagick": "^3.4.4",
-    "ext-json": ">=7.4"
+    "ext-json": ">=8.1"
   },
   "require-dev": {
-    "phpunit/phpunit": "^9.5"
+    "phpunit/phpunit": "^10.0"
   },
   "support": {
     "issues": "https://github.com/nohn/watermeter/issues"
diff --git a/phpunit.xml b/phpunit.xml
index 4d242c1..6d9ded3 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,27 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
-         bootstrap="vendor/autoload.php"
-         cacheResultFile=".phpunit.cache/test-results"
-         executionOrder="depends,defects"
-         forceCoversAnnotation="false"
-         beStrictAboutCoversAnnotation="false"
-         beStrictAboutOutputDuringTests="false"
-         beStrictAboutTodoAnnotatedTests="false"
-         convertDeprecationsToExceptions="true"
-         failOnRisky="true"
-         failOnWarning="true"
-         verbose="true">
-    <testsuites>
-        <testsuite name="default">
-            <directory>tests</directory>
-        </testsuite>
-    </testsuites>
-
-    <coverage cacheDirectory=".phpunit.cache/code-coverage"
-              processUncoveredFiles="true">
-        <include>
-            <directory suffix=".php">classes</directory>
-        </include>
-    </coverage>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd" bootstrap="vendor/autoload.php" executionOrder="depends,defects" beStrictAboutOutputDuringTests="false" failOnRisky="true" failOnWarning="true" cacheDirectory=".phpunit.cache" requireCoverageMetadata="false" beStrictAboutCoverageMetadata="false">
+  <testsuites>
+    <testsuite name="default">
+      <directory>tests</directory>
+    </testsuite>
+  </testsuites>
+  <source>
+    <include>
+      <directory suffix=".php">classes</directory>
+    </include>
+  </source>
 </phpunit>
diff --git a/phpunit.xml.bak b/phpunit.xml.bak
new file mode 100644
index 0000000..4d242c1
--- /dev/null
+++ b/phpunit.xml.bak
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         cacheResultFile=".phpunit.cache/test-results"
+         executionOrder="depends,defects"
+         forceCoversAnnotation="false"
+         beStrictAboutCoversAnnotation="false"
+         beStrictAboutOutputDuringTests="false"
+         beStrictAboutTodoAnnotatedTests="false"
+         convertDeprecationsToExceptions="true"
+         failOnRisky="true"
+         failOnWarning="true"
+         verbose="true">
+    <testsuites>
+        <testsuite name="default">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <coverage cacheDirectory=".phpunit.cache/code-coverage"
+              processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">classes</directory>
+        </include>
+    </coverage>
+</phpunit>