diff --git a/.github/actions/resolve-php-version/action.yml b/.github/actions/resolve-php-version/action.yml
new file mode 100644
index 00000000..fd4b2870
--- /dev/null
+++ b/.github/actions/resolve-php-version/action.yml
@@ -0,0 +1,149 @@
+name: Resolve PHP Version
+description: Resolve the PHP version and test matrix from composer.lock or composer.json.
+
+outputs:
+  php-version:
+    description: Resolved PHP version used by setup-php.
+    value: ${{ steps.resolve.outputs.php-version }}
+  php-version-source:
+    description: Source used to resolve the PHP version.
+    value: ${{ steps.resolve.outputs.php-version-source }}
+  test-matrix:
+    description: JSON matrix of supported PHP minors starting from the inferred minimum.
+    value: ${{ steps.resolve.outputs.test-matrix }}
+  warning:
+    description: Warning emitted when the workflow falls back to the default PHP version.
+    value: ${{ steps.resolve.outputs.warning }}
+
+runs:
+  using: composite
+  steps:
+    - name: Resolve workflow PHP version
+      id: resolve
+      shell: bash
+      run: |
+        python3 <<'PY'
+        from __future__ import annotations
+
+        import json
+        import os
+        import re
+        from pathlib import Path
+
+        SUPPORTED_MINORS = ["8.3", "8.4", "8.5"]
+        DEFAULT_PHP_VERSION = "8.3"
+
+        def version_to_tuple(version: str) -> tuple[int, int]:
+            major, minor = version.split(".")
+            return int(major), int(minor)
+
+        def normalize_minor(version: str) -> str | None:
+            match = re.match(r"^\s*v?(8)\.(\d+)(?:\.\d+)?(?:\.\*)?\s*$", version)
+            if match is None:
+                return None
+            return f"{match.group(1)}.{match.group(2)}"
+
+        def next_supported_minor(version: str) -> str | None:
+            if version not in SUPPORTED_MINORS:
+                return None
+            index = SUPPORTED_MINORS.index(version) + 1
+            if index >= len(SUPPORTED_MINORS):
+                major, minor = version_to_tuple(version)
+                return f"{major}.{minor + 1}"
+            return SUPPORTED_MINORS[index]
+
+        def infer_clause_lower_bound(clause: str) -> str | None:
+            tokens = re.findall(r"(\^|~|>=|>|<=|<|==|=)?\s*v?(8\.\d+(?:\.\d+)?(?:\.\*)?)", clause)
+            lower_bounds: list[str] = []
+            for operator, version in tokens:
+                normalized = normalize_minor(version)
+                if normalized is None:
+                    continue
+                if operator in ("", "=", "==", "^", "~", ">="):
+                    lower_bounds.append(normalized)
+                    continue
+                if operator == ">":
+                    next_minor = next_supported_minor(normalized)
+                    if next_minor is not None:
+                        lower_bounds.append(next_minor)
+            if not lower_bounds:
+                return None
+            return max(lower_bounds, key=version_to_tuple)
+
+        def infer_minimum_supported_minor(requirement: str) -> str | None:
+            clauses = [clause.strip() for clause in requirement.split("||")]
+            lower_bounds = [
+                clause_lower_bound
+                for clause in clauses
+                if (clause_lower_bound := infer_clause_lower_bound(clause)) is not None
+            ]
+            if not lower_bounds:
+                return None
+            return min(lower_bounds, key=version_to_tuple)
+
+        def resolve_from_lock(composer_lock: Path) -> tuple[str | None, str | None]:
+            if not composer_lock.exists():
+                return None, None
+            try:
+                payload = json.loads(composer_lock.read_text())
+            except json.JSONDecodeError:
+                return None, "composer.lock exists but could not be parsed"
+            platform_overrides = payload.get("platform-overrides") or {}
+            platform_php = platform_overrides.get("php")
+            if isinstance(platform_php, str):
+                resolved = normalize_minor(platform_php)
+                if resolved is not None:
+                    return resolved, "composer.lock platform-overrides.php"
+                return None, "composer.lock platform-overrides.php is not a supported PHP version"
+            return None, None
+
+        def resolve_from_json(composer_json: Path) -> tuple[str | None, str | None]:
+            if not composer_json.exists():
+                return None, "composer.json does not exist"
+            try:
+                payload = json.loads(composer_json.read_text())
+            except json.JSONDecodeError:
+                return None, "composer.json could not be parsed"
+            config_platform_php = (((payload.get("config") or {}).get("platform") or {}).get("php"))
+            if isinstance(config_platform_php, str):
+                resolved = normalize_minor(config_platform_php)
+                if resolved is not None:
+                    return resolved, "composer.json config.platform.php"
+                return None, "composer.json config.platform.php is not a supported PHP version"
+            require_php = ((payload.get("require") or {}).get("php"))
+            if isinstance(require_php, str):
+                resolved = infer_minimum_supported_minor(require_php)
+                if resolved is not None:
+                    return resolved, "composer.json require.php"
+                return None, "composer.json require.php could not be resolved safely"
+            return None, None
+
+        def resolve_php_version() -> tuple[str, str, str | None]:
+            resolved, source = resolve_from_lock(Path("composer.lock"))
+            if resolved is None:
+                resolved, source = resolve_from_json(Path("composer.json"))
+            if resolved is None:
+                return DEFAULT_PHP_VERSION, "fallback", "No reliable PHP version source was found. Falling back to 8.3."
+            if resolved not in SUPPORTED_MINORS:
+                return DEFAULT_PHP_VERSION, "fallback", (
+                    f"Resolved PHP version {resolved} from {source} is outside the supported CI policy. Falling back to 8.3."
+                )
+            return resolved, source or "fallback", None
+
+        resolved_version, source, warning = resolve_php_version()
+        matrix_versions = [version for version in SUPPORTED_MINORS if version_to_tuple(version) >= version_to_tuple(resolved_version)]
+        matrix = json.dumps({"php-version": matrix_versions}, separators=(",", ":"))
+
+        print(f"Resolved PHP version source: {source}")
+        print(f"Resolved PHP version: {resolved_version}")
+        print(f"Resolved PHP test matrix: {matrix_versions}")
+        if warning:
+            print(f"Warning: {warning}")
+
+        github_output = os.environ["GITHUB_OUTPUT"]
+        with open(github_output, "a", encoding="utf-8") as handle:
+            handle.write(f"php-version={resolved_version}\n")
+            handle.write(f"php-version-source={source}\n")
+            handle.write(f"test-matrix={matrix}\n")
+            handle.write(f"warning={warning or ''}\n")
+        PY
diff --git a/.github/wiki b/.github/wiki
index 5246f541..5387fef9 160000
--- a/.github/wiki
+++ b/.github/wiki
@@ -1 +1 @@
-Subproject commit 5246f541a761712275b04ddd4dab1b135ace89f6
+Subproject commit 5387fef9e237adc67cb096510d692f320fbeaba3
diff --git a/.github/workflows/reports.yml b/.github/workflows/reports.yml
index 94940d2c..f6e77ce2 100644
--- a/.github/workflows/reports.yml
+++ b/.github/workflows/reports.yml
@@ -30,7 +30,22 @@ concurrency:
     cancel-in-progress: ${{ github.event_name == 'pull_request' && github.event.action != 'closed' }}
 
 jobs:
+    resolve_php:
+        name: Resolve PHP Version
+        runs-on: ubuntu-latest
+        outputs:
+            php-version: ${{ steps.resolve.outputs.php-version }}
+            php-version-source: ${{ steps.resolve.outputs.php-version-source }}
+
+        steps:
+            - uses: actions/checkout@v6
+
+            - name: Resolve workflow PHP version
+              id: resolve
+              uses: php-fast-forward/dev-tools/.github/actions/resolve-php-version@main
+
     reports:
+        needs: resolve_php
         if: github.event_name != 'schedule' && !(github.event_name == 'workflow_dispatch' && inputs.cleanup-previews) && (github.event_name != 'pull_request' || github.event.action != 'closed')
         name: Generate Reports
         runs-on: ubuntu-latest
@@ -49,7 +64,7 @@ jobs:
             - name: Setup PHP
               uses: shivammathur/setup-php@v2
               with:
-                php-version: '8.3'
+                php-version: ${{ needs.resolve_php.outputs.php-version }}
                 extensions: pcov, pcntl
                 coverage: pcov
 
@@ -57,8 +72,9 @@ jobs:
               uses: actions/cache@v5
               with:
                 path: /tmp/composer-cache
-                key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+                key: ${{ runner.os }}-composer-${{ needs.resolve_php.outputs.php-version }}-${{ hashFiles('**/composer.lock') }}
                 restore-keys: |
+                  ${{ runner.os }}-composer-${{ needs.resolve_php.outputs.php-version }}-
                   ${{ runner.os }}-composer-
 
             - name: Install dependencies
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c3b8345f..cc8a03ca 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -41,6 +41,7 @@ on:
           - 'tests/**'
           - 'composer.json'
           - 'composer.lock'
+          - '.github/actions/**'
           - '.github/workflows/tests.yml'
     push:
         branches: [ "main" ]
@@ -53,12 +54,27 @@ concurrency:
     cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
+    resolve_php:
+        name: Resolve PHP Version
+        runs-on: ubuntu-latest
+        outputs:
+            php-version: ${{ steps.resolve.outputs.php-version }}
+            php-version-source: ${{ steps.resolve.outputs.php-version-source }}
+            test-matrix: ${{ steps.resolve.outputs.test-matrix }}
+
+        steps:
+            - uses: actions/checkout@v6
+
+            - name: Resolve workflow PHP version
+              id: resolve
+              uses: php-fast-forward/dev-tools/.github/actions/resolve-php-version@main
+
     tests:
+        needs: resolve_php
         name: Run Tests
         runs-on: ubuntu-latest
         strategy:
-            matrix:
-                php-version: [ '8.3', '8.4', '8.5' ]
+            matrix: ${{ fromJson(needs.resolve_php.outputs.test-matrix) }}
         env:
             TESTS_ROOT_VERSION: ${{ github.event_name == 'pull_request' && format('dev-{0}', github.event.pull_request.head.ref) || 'dev-main' }}
         steps:
@@ -75,8 +91,9 @@ jobs:
               uses: actions/cache@v5
               with:
                 path: /tmp/composer-cache
-                key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+                key: ${{ runner.os }}-composer-${{ matrix.php-version }}-${{ hashFiles('**/composer.lock') }}
                 restore-keys: |
+                  ${{ runner.os }}-composer-${{ matrix.php-version }}-
                   ${{ runner.os }}-composer-
 
             - name: Mark workspace as safe for git
@@ -106,6 +123,7 @@ jobs:
               run: composer dev-tools tests -- --coverage=.dev-tools/coverage --min-coverage=${{ steps.minimum-coverage.outputs.value }}
 
     dependency-health:
+        needs: resolve_php
         name: Dependency Health
         if: ${{ github.event_name != 'workflow_call' || inputs.run-dependencies-check }}
         runs-on: ubuntu-latest
@@ -118,14 +136,15 @@ jobs:
             - name: Setup PHP
               uses: shivammathur/setup-php@v2
               with:
-                php-version: '8.3'
+                php-version: ${{ needs.resolve_php.outputs.php-version }}
 
             - name: Cache Composer dependencies
               uses: actions/cache@v5
               with:
                 path: /tmp/composer-cache
-                key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+                key: ${{ runner.os }}-composer-${{ needs.resolve_php.outputs.php-version }}-${{ hashFiles('**/composer.lock') }}
                 restore-keys: |
+                  ${{ runner.os }}-composer-${{ needs.resolve_php.outputs.php-version }}-
                   ${{ runner.os }}-composer-
 
             - name: Mark workspace as safe for git
diff --git a/.github/workflows/wiki.yml b/.github/workflows/wiki.yml
index 4b2b3ef1..2c360d66 100644
--- a/.github/workflows/wiki.yml
+++ b/.github/workflows/wiki.yml
@@ -18,7 +18,22 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  resolve_php:
+    name: Resolve PHP Version
+    runs-on: ubuntu-latest
+    outputs:
+      php-version: ${{ steps.resolve.outputs.php-version }}
+      php-version-source: ${{ steps.resolve.outputs.php-version-source }}
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Resolve workflow PHP version
+        id: resolve
+        uses: php-fast-forward/dev-tools/.github/actions/resolve-php-version@main
+
   preview:
+    needs: resolve_php
     name: Update Wiki Preview
     if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
@@ -42,14 +57,15 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '8.3'
+          php-version: ${{ needs.resolve_php.outputs.php-version }}
 
       - name: Cache Composer dependencies
         uses: actions/cache@v5
         with:
           path: /tmp/composer-cache
-          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          key: ${{ runner.os }}-composer-${{ needs.resolve_php.outputs.php-version }}-${{ hashFiles('**/composer.lock') }}
           restore-keys: |
+            ${{ runner.os }}-composer-${{ needs.resolve_php.outputs.php-version }}-
             ${{ runner.os }}-composer-
 
       - name: Mark workspace as safe for git
diff --git a/docs/usage/github-actions.rst b/docs/usage/github-actions.rst
index 3d12103b..1ac2ef00 100644
--- a/docs/usage/github-actions.rst
+++ b/docs/usage/github-actions.rst
@@ -34,6 +34,7 @@ The ``reports.yml`` workflow is responsible for generating technical documentati
 **Behavior:**
 *   **Main Branch**: Runs all checks and deploys the final reports to the root of the ``gh-pages`` branch.
     *   Runs a post-deploy health check against the published reports index and coverage URLs with retry/backoff to account for Pages propagation.
+    *   Resolves the workflow PHP version from ``composer.lock`` or ``composer.json`` before installing dependencies.
 *   **Pull Requests**:
     *   Generates a **Preview** of the documentation, coverage, and metrics.
     *   Deploys the preview to ``gh-pages`` under ``previews/pr-{number}/``.
@@ -51,6 +52,7 @@ The ``wiki.yml`` workflow synchronizes the documentation generated by the ``dev-
 **Behavior:**
 *   **Submodule Management**: It manages a submodule at ``.github/wiki`` that points to the actual wiki repository.
 *   **Pull Requests**: Pushes documentation changes to a dedicated branch (e.g., ``pr-123``) in the wiki repository for review.
+*   **PHP Version Resolution**: Resolves the PHP version from ``composer.lock`` or ``composer.json`` before setting up PHP and installing dependencies.
 *   **Merge**: When a PR is merged into ``main``, it pushes the changes to the ``master`` branch of the wiki, validates the remote branch SHA, and makes them live.
 *   **Cleanup**: When a PR is closed, the workflow deletes the matching wiki preview branch. A scheduled cleanup also removes stale ``pr-{number}`` branches for already closed pull requests.
 
@@ -65,6 +67,7 @@ Fast Forward Tests
 The ``tests.yml`` workflow provides standard Continuous Integration.
 
 *   Runs PHPUnit tests across the supported PHP matrix.
+*   Resolves the minimum supported PHP minor version from ``composer.lock`` or ``composer.json`` and builds the test matrix from that floor upward.
 *   Runs dependency health as a separate non-blocking job when enabled.
 *   Uses PR-scoped concurrency so newer pushes cancel older in-progress runs for the same pull request.