diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 2e94d38..8c14d39 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -48,29 +48,7 @@ jobs:
   benchmark:
     name: "Benchmark"
     runs-on: "ubuntu-latest"
-    strategy:
-      matrix:
-        php-version:
-          - "7.2"
-          - "7.3"
-          - "7.4"
-          - "8.0"
-    steps:
-      - uses: "actions/checkout@v2"
-      - uses: "shivammathur/setup-php@v2"
-        with:
-          php-version: "${{ matrix.php-version }}"
-          tools: pecl
-          extensions: bcmath, ctype, gmp
-          coverage: "none"
-          ini-values: "memory_limit=-1"
-      - uses: "ramsey/composer-install@v1"
-      - name: "Run PHPBench"
-        run: "composer phpbench -- --ansi"
-
-  unit-tests:
-    name: "Unit Tests"
-    runs-on: "ubuntu-latest"
+    continue-on-error: ${{ matrix.experimental }}
     strategy:
       fail-fast: false
       matrix:
@@ -78,17 +56,54 @@ jobs:
           - "7.2"
           - "7.3"
           - "7.4"
-          - "8.0"
+        experimental:
+          - false
+        include:
+          - php-version: "8.0"
+            experimental: true
+            composer-options: "--ignore-platform-reqs"
+    steps:
+      - uses: "actions/checkout@v2"
+      - uses: "shivammathur/setup-php@v2"
+        with:
+          php-version: "${{ matrix.php-version }}"
+          extensions: bcmath, ctype, gmp
+          coverage: "none"
+          ini-values: "memory_limit=-1"
+      - uses: "ramsey/composer-install@v1"
+        with:
+          composer-options: "${{ matrix.composer-options }}"
+      - name: "Run PHPBench"
+        run: "composer phpbench -- --ansi"
+
+  unit-tests:
+    name: "Unit Tests"
+    runs-on: "ubuntu-latest"
+    continue-on-error: ${{ matrix.experimental }}
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+          - "7.2"
+          - "7.3"
+          - "7.4"
+        experimental:
+          - false
+        include:
+          - php-version: "8.0"
+            experimental: true
+            composer-options: "--ignore-platform-reqs"
     steps:
       - uses: "actions/checkout@v2"
       - uses: "shivammathur/setup-php@v2"
         with:
           php-version: "${{ matrix.php-version }}"
-          tools: pecl
           extensions: bcmath, ctype, gmp
           coverage: "pcov"
           ini-values: "memory_limit=-1"
       - uses: "ramsey/composer-install@v1"
+        with:
+          composer-options: "${{ matrix.composer-options }}"
       - name: "Run unit tests"
         run: "./vendor/bin/phpunit --verbose --colors=always --coverage-clover build/logs/clover.xml --coverage-text"
       - name: "Publish coverage report to Codecov"
diff --git a/composer.json b/composer.json
index 41d500b..ea1a95d 100644
--- a/composer.json
+++ b/composer.json
@@ -36,7 +36,7 @@
         "psy/psysh": "^0.10.0",
         "slevomat/coding-standard": "^6.0",
         "squizlabs/php_codesniffer": "^3.5",
-        "vimeo/psalm": "3.9.4"
+        "vimeo/psalm": "^3.18"
     },
     "suggest": {
         "ext-bcmath": "Enables faster math with arbitrary-precision integers using BCMath.",
diff --git a/tests/psalm-baseline.xml b/tests/psalm-baseline.xml
index be0e7de..2744786 100644
--- a/tests/psalm-baseline.xml
+++ b/tests/psalm-baseline.xml
@@ -1,48 +1,52 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<files psalm-version="3.9.4@352bd3f5c5789db04e4010856c2f4e01ed354f4e">
+<files psalm-version="3.18.2@19aa905f7c3c7350569999a93c40ae91ae4e1626">
   <file src="src/Builder/DegradedUuidBuilder.php">
     <DeprecatedClass occurrences="3">
-      <code>new DegradedTimeConverter()</code>
       <code>DegradedUuid</code>
+      <code>new DegradedTimeConverter()</code>
     </DeprecatedClass>
+    <ImpureVariable occurrences="2">
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
+  </file>
+  <file src="src/Builder/FallbackBuilder.php">
+    <ImpureMethodCall occurrences="1"/>
+    <ImpureVariable occurrences="1">
+      <code>$this</code>
+    </ImpureVariable>
+  </file>
+  <file src="src/Converter/Number/BigNumberConverter.php">
+    <ImpureVariable occurrences="2">
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
   </file>
   <file src="src/Converter/Number/DegradedNumberConverter.php">
     <DeprecatedClass occurrences="1">
       <code>BigNumberConverter</code>
     </DeprecatedClass>
   </file>
+  <file src="src/Converter/Number/GenericNumberConverter.php">
+    <ImpureVariable occurrences="2">
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
+  </file>
   <file src="src/Converter/Time/DegradedTimeConverter.php">
     <DeprecatedClass occurrences="1">
       <code>BigNumberTimeConverter</code>
     </DeprecatedClass>
   </file>
-  <file src="src/Converter/Time/PhpTimeConverter.php">
-    <InvalidOperand occurrences="2">
-      <code>$uuidTime</code>
-      <code>$uuidTime</code>
-    </InvalidOperand>
-  </file>
-  <file src="src/Generator/PeclUuidRandomGenerator.php">
-    <MixedAssignment occurrences="1">
-      <code>$uuid</code>
-    </MixedAssignment>
-    <MixedInferredReturnType occurrences="1">
-      <code>string</code>
-    </MixedInferredReturnType>
-    <MixedReturnStatement occurrences="1">
-      <code>uuid_parse($uuid)</code>
-    </MixedReturnStatement>
-  </file>
-  <file src="src/Generator/PeclUuidTimeGenerator.php">
-    <MixedAssignment occurrences="1">
-      <code>$uuid</code>
-    </MixedAssignment>
-    <MixedInferredReturnType occurrences="1">
-      <code>string</code>
-    </MixedInferredReturnType>
-    <MixedReturnStatement occurrences="1">
-      <code>uuid_parse($uuid)</code>
-    </MixedReturnStatement>
+  <file src="src/FeatureSet.php">
+    <PropertyNotSetInConstructor occurrences="6">
+      <code>$calculator</code>
+      <code>$dceSecurityGenerator</code>
+      <code>$numberConverter</code>
+      <code>$timeConverter</code>
+      <code>$timeGenerator</code>
+      <code>$timeProvider</code>
+    </PropertyNotSetInConstructor>
   </file>
   <file src="src/Generator/PeclUuidNameGenerator.php">
     <ImpureFunctionCall occurrences="3">
@@ -51,12 +55,26 @@
       <code>uuid_parse</code>
     </ImpureFunctionCall>
   </file>
+  <file src="src/Guid/GuidBuilder.php">
+    <ImpureVariable occurrences="3">
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
+  </file>
+  <file src="src/Nonstandard/UuidBuilder.php">
+    <ImpureVariable occurrences="3">
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
+  </file>
   <file src="src/Provider/Dce/SystemDceSecurityProvider.php">
     <ForbiddenCode occurrences="5">
-      <code>shell_exec('id -u')</code>
       <code>shell_exec('id -g')</code>
-      <code>shell_exec('whoami /user /fo csv /nh')</code>
+      <code>shell_exec('id -u')</code>
       <code>shell_exec('net user %username% | findstr /b /i "Local Group Memberships"')</code>
+      <code>shell_exec('whoami /user /fo csv /nh')</code>
       <code>shell_exec('wmic group get name,sid | findstr /b /i ' . escapeshellarg($firstGroup))</code>
     </ForbiddenCode>
   </file>
@@ -64,9 +82,31 @@
     <MixedArgument occurrences="1">
       <code>$macs</code>
     </MixedArgument>
-    <MixedAssignment occurrences="1">
-      <code>$node</code>
-    </MixedAssignment>
+    <MixedArrayAccess occurrences="1">
+      <code>$macs</code>
+    </MixedArrayAccess>
+    <MixedArrayAssignment occurrences="1">
+      <code>$macs[]</code>
+    </MixedArrayAssignment>
+  </file>
+  <file src="src/Rfc4122/UuidBuilder.php">
+    <ImpureVariable occurrences="15">
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
   </file>
   <file src="src/Uuid.php">
     <ImpureMethodCall occurrences="6">
@@ -78,4 +118,30 @@
       <code>getFactory</code>
     </ImpureMethodCall>
   </file>
+  <file src="src/UuidFactory.php">
+    <ImpurePropertyFetch occurrences="7">
+      <code>$this-&gt;codec</code>
+      <code>$this-&gt;codec</code>
+      <code>$this-&gt;codec</code>
+      <code>$this-&gt;isDefaultFeatureSet</code>
+      <code>$this-&gt;nameGenerator</code>
+      <code>$this-&gt;numberConverter</code>
+      <code>$this-&gt;uuidBuilder</code>
+    </ImpurePropertyFetch>
+    <ImpureVariable occurrences="13">
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+      <code>$this</code>
+    </ImpureVariable>
+  </file>
 </files>