diff --git a/composer.json b/composer.json
index 9542fc5a1..3bc3e3675 100644
--- a/composer.json
+++ b/composer.json
@@ -61,7 +61,7 @@
             "php artisan package:discover"
         ],
         "post-update-cmd": [
-            "php artisan october:util set build",
+            "php artisan october:version",
             "php artisan package:discover"
         ],
         "test": [
diff --git a/modules/system/ServiceProvider.php b/modules/system/ServiceProvider.php
index eb5b6c613..239465b46 100644
--- a/modules/system/ServiceProvider.php
+++ b/modules/system/ServiceProvider.php
@@ -133,7 +133,7 @@ class ServiceProvider extends ModuleServiceProvider
     protected function registerPrivilegedActions()
     {
         $requests = ['/combine/', '@/system/updates', '@/system/install', '@/backend/auth'];
-        $commands = ['october:up', 'october:update'];
+        $commands = ['october:up', 'october:update', 'october:version'];
 
         /*
          * Requests
@@ -248,6 +248,8 @@ class ServiceProvider extends ModuleServiceProvider
         $this->registerConsoleCommand('october.env', 'System\Console\OctoberEnv');
         $this->registerConsoleCommand('october.install', 'System\Console\OctoberInstall');
         $this->registerConsoleCommand('october.passwd', 'System\Console\OctoberPasswd');
+        $this->registerConsoleCommand('october.version', 'System\Console\OctoberVersion');
+        $this->registerConsoleCommand('october.manifest', 'System\Console\OctoberManifest');
 
         $this->registerConsoleCommand('plugin.install', 'System\Console\PluginInstall');
         $this->registerConsoleCommand('plugin.remove', 'System\Console\PluginRemove');
diff --git a/modules/system/classes/FileManifest.php b/modules/system/classes/FileManifest.php
new file mode 100644
index 000000000..a54b50ea3
--- /dev/null
+++ b/modules/system/classes/FileManifest.php
@@ -0,0 +1,193 @@
+<?php namespace System\Classes;
+
+use ApplicationException;
+use Config;
+use October\Rain\Filesystem\Filesystem;
+use October\Rain\Halcyon\Datasource\FileDatasource;
+
+/**
+ * Stores the file manifest for this October CMS installation.
+ *
+ * This manifest is a file checksum of all files within this October CMS installation. When compared to the source
+ * manifest, this allows us to determine the current installation's build number.
+ *
+ * @package october\system
+ * @author Ben Thomson
+ */
+class FileManifest
+{
+    /**
+     * @var string Root folder of this installation.
+     */
+    protected $root;
+
+    /**
+     * @var array Modules to store in manifest.
+     */
+    protected $modules = ['system', 'backend', 'cms'];
+
+    /**
+     * @var array Files cache.
+     */
+    protected $files = [];
+
+    /**
+     * Constructor.
+     *
+     * @param string $root The root folder to get the file list from.
+     * @param array $modules An array of modules to include in the file manifest.
+     */
+    public function __construct($root = null, array $modules = null)
+    {
+        if (isset($root)) {
+            $this->setRoot($root);
+        } else {
+            $this->setRoot(base_path());
+        }
+
+        if (isset($modules)) {
+            $this->setModules($modules);
+        } else {
+            $this->setModules(Config::get('cms.loadModules', ['System', 'Backend', 'Cms']));
+        }
+    }
+
+    /**
+     * Sets the root folder.
+     *
+     * @param string $root
+     * @throws ApplicationException If the specified root does not exist.
+     */
+    public function setRoot($root)
+    {
+        if (is_string($root)) {
+            $this->root = realpath($root);
+
+            if ($this->root === false || !is_dir($this->root)) {
+                throw new ApplicationException(
+                    'Invalid root specified for the file manifest.'
+                );
+            }
+        }
+
+        return $this;
+    }
+
+    /**
+     * Sets the modules.
+     *
+     * @param array $modules
+     */
+    public function setModules(array $modules)
+    {
+        $this->modules = array_map(function ($module) {
+            return strtolower($module);
+        }, $modules);
+
+        return $this;
+    }
+
+    /**
+     * Gets a list of files and their corresponding hashsums.
+     *
+     * @return array
+     */
+    public function getFiles()
+    {
+        if (count($this->files)) {
+            return $this->files;
+        }
+
+        $files = [];
+
+        foreach ($this->modules as $module) {
+            $path = $this->root . '/modules/' . $module;
+
+            if (!is_dir($path)) {
+                continue;
+            }
+
+            foreach ($this->findFiles($path) as $file) {
+                $files[$this->getFilename($file)] = hash('sha3-256', $this->normalizeFileContents($file));
+            }
+        }
+
+        return $this->files = $files;
+    }
+
+    /**
+     * Gets the checksum of a specific install.
+     *
+     * @return array
+     */
+    public function getModuleChecksums()
+    {
+        if (!count($this->files)) {
+            $this->getFiles();
+        }
+
+        $modules = [];
+        foreach ($this->modules as $module) {
+            $modules[$module] = '';
+        }
+
+        foreach ($this->files as $path => $hash) {
+            // Determine module
+            $module = explode('/', $path)[2];
+
+            $modules[$module] .= $hash;
+        }
+
+        return array_map(function ($moduleSum) {
+            return hash('sha3-256', $moduleSum);
+        }, $modules);
+    }
+
+    /**
+     * Finds all files within the path.
+     *
+     * @param string $basePath The base path to look for files within.
+     * @return array
+     */
+    protected function findFiles(string $basePath)
+    {
+        $datasource = new FileDatasource($basePath, new Filesystem);
+
+        $files = array_map(function ($path) use ($basePath) {
+            return $basePath . '/' . $path;
+        }, array_keys($datasource->getAvailablePaths()));
+
+        // Ensure files are sorted so they are in a consistent order, no matter the way the OS returns the file list.
+        sort($files, SORT_NATURAL);
+
+        return $files;
+    }
+
+    /**
+     * Returns the filename without the root.
+     *
+     * @param string $file
+     * @return string
+     */
+    protected function getFilename(string $file): string
+    {
+        return str_replace($this->root, '', $file);
+    }
+
+    /**
+     * Normalises the file contents, irrespective of OS.
+     *
+     * @param string $file
+     * @return string
+     */
+    protected function normalizeFileContents(string $file): string
+    {
+        if (!is_file($file)) {
+            return '';
+        }
+
+        $contents = file_get_contents($file);
+
+        return str_replace(PHP_EOL, "\n", $contents);
+    }
+}
diff --git a/modules/system/classes/SourceManifest.php b/modules/system/classes/SourceManifest.php
new file mode 100644
index 000000000..9e154e078
--- /dev/null
+++ b/modules/system/classes/SourceManifest.php
@@ -0,0 +1,356 @@
+<?php namespace System\Classes;
+
+use ApplicationException;
+use Config;
+
+/**
+ * Reads and stores the October CMS source manifest information.
+ *
+ * The source manifest is a meta JSON file, stored on GitHub, that contains the hashsums of all module files across all
+ * buils of October CMS. This allows us to compare the October CMS installation against the expected file checksums and
+ * determine the installed build and whether it has been modified.
+ *
+ * @package october\system
+ * @author Ben Thomson
+ */
+class SourceManifest
+{
+    /**
+     * @var string The URL to the source manifest
+     */
+    protected $source;
+
+    /**
+     * @var array Array of builds, keyed by build number, with files for keys and hashes for values.
+     */
+    protected $builds = [];
+
+    /**
+     * Constructor
+     *
+     * @param string $manifest Manifest file to load
+     * @param bool $autoload Loads the manifest on construct
+     */
+    public function __construct($source = null, $autoload = true)
+    {
+        if (isset($source)) {
+            $this->setSource($source);
+        } else {
+            $this->setSource(
+                Config::get(
+                    'cms.sourceManifestUrl',
+                    'https://raw.githubusercontent.com/octoberrain/meta/master/manifest/builds.json'
+                )
+            );
+        }
+
+        if ($autoload) {
+            $this->load();
+        }
+    }
+
+    /**
+     * Sets the source manifest URL.
+     *
+     * @param string $source
+     * @return void
+     */
+    public function setSource($source)
+    {
+        if (is_string($source)) {
+            $this->source = $source;
+        }
+    }
+
+    /**
+     * Loads the manifest file.
+     *
+     * @throws ApplicationException If the manifest is invalid, or cannot be parsed.
+     */
+    public function load()
+    {
+        $source = file_get_contents($this->source);
+        if (empty($source)) {
+            throw new ApplicationException(
+                'Source manifest not found'
+            );
+        }
+
+        $data = json_decode($source, true);
+
+        if (json_last_error() !== JSON_ERROR_NONE) {
+            throw new ApplicationException(
+                'Unable to decode source manifest JSON data. JSON Error: ' . json_last_error_msg()
+            );
+        }
+        if (!isset($data['manifest']) || !is_array($data['manifest'])) {
+            throw new ApplicationException(
+                'The source manifest at "' . $this->source . '" does not appear to be a valid source manifest file.'
+            );
+        }
+
+        foreach ($data['manifest'] as $build) {
+            $this->builds[$build['build']] = [
+                'modules' => $build['modules'],
+                'files' => $build['files'],
+            ];
+        }
+
+        return $this;
+    }
+
+    /**
+     * Adds a FileManifest instance as a build to this source manifest.
+     *
+     * Changes between builds are calculated and stored with the build. Builds are stored numerically, in ascending
+     * order.
+     *
+     * @param integer $build Build number.
+     * @param FileManifest $manifest The file manifest to add as a build.
+     * @param integer $previous The previous build number, used to determine changes with this build.
+     * @return void
+     */
+    public function addBuild($build, FileManifest $manifest, $previous = null)
+    {
+        $this->builds[(int) $build] = [
+            'modules' => $manifest->getModuleChecksums(),
+            'files' => $this->processChanges($manifest, $previous),
+        ];
+
+        // Sort builds numerically in ascending order.
+        ksort($this->builds[$build], SORT_NUMERIC);
+    }
+
+    /**
+     * Gets all builds.
+     *
+     * @return array
+     */
+    public function getBuilds()
+    {
+        return $this->builds;
+    }
+
+    /**
+     * Gets the maximum build number in the manifest.
+     *
+     * @return int
+     */
+    public function getMaxBuild()
+    {
+        if (!count($this->builds)) {
+            return null;
+        }
+
+        return max(array_keys($this->builds));
+    }
+
+    /**
+     * Generates the JSON data to be stored with the source manifest.
+     *
+     * @throws ApplicationException If no builds have been added to this source manifest.
+     * @return string
+     */
+    public function generate()
+    {
+        if (!count($this->builds)) {
+            throw new ApplicationException(
+                'No builds have been added to the manifest.'
+            );
+        }
+
+        $json = [
+            'manifest' => [],
+        ];
+
+        foreach ($this->builds as $build => $details) {
+            $json['manifest'][] = [
+                'build' => $build,
+                'modules' => $details['modules'],
+                'files' => $details['files'],
+            ];
+        }
+
+        return json_encode($json, JSON_PRETTY_PRINT);
+    }
+
+    /**
+     * Gets the filelist state at a selected build.
+     *
+     * This method will list all expected files and hashsums at the specified build number.
+     *
+     * @param integer $build Build number to get the filelist state for.
+     * @throws ApplicationException If the specified build has not been added to the source manifest.
+     * @return array
+     */
+    public function getState($build)
+    {
+        if (!isset($this->builds[$build])) {
+            throw new \Exception('The specified build has not been added.');
+        }
+
+        $state = [];
+
+        foreach ($this->builds as $number => $details) {
+            if (isset($details['files']['added'])) {
+                foreach ($details['files']['added'] as $filename => $sum) {
+                    $state[$filename] = $sum;
+                }
+            }
+            if (isset($details['files']['modified'])) {
+                foreach ($details['files']['modified'] as $filename => $sum) {
+                    $state[$filename] = $sum;
+                }
+            }
+            if (isset($details['files']['removed'])) {
+                foreach ($details['files']['removed'] as $filename) {
+                    unset($state[$filename]);
+                }
+            }
+
+            if ($number === $build) {
+                break;
+            }
+        }
+
+        return $state;
+    }
+
+    /**
+     * Compares a file manifest with the source manifest.
+     *
+     * This will determine the build of the October CMS installation.
+     *
+     * @param FileManifest $manifest The file manifest to compare against the source.
+     * @return array|null Will return an array with the build, modified state and the probability that it is the
+     *  version specified. If the detected version does not look like a likely candidate, this will return null.
+     */
+    public function compare(FileManifest $manifest)
+    {
+        $modules = $manifest->getModuleChecksums();
+
+        // Look for an unmodified version
+        foreach ($this->getBuilds() as $build => $details) {
+            $matched = array_intersect_assoc($details['modules'], $modules);
+
+            if (count($matched) === count($modules)) {
+                return [
+                    'build' => $build,
+                    'modified' => false,
+                ];
+            }
+        }
+
+        // If we could not find an unmodified version, try to find the closest version and assume this is a modified
+        // install.
+        $buildMatch = [];
+
+        foreach ($this->getBuilds() as $build => $details) {
+            $state = $this->getState($build);
+
+            // Include only the files that match the modules being loaded in this file manifest
+            $availableModules = array_keys($modules);
+
+            foreach ($state as $file => $sum) {
+                // Determine module
+                $module = explode('/', $file)[2];
+
+                if (!in_array($module, $availableModules)) {
+                    unset($state[$file]);
+                }
+            }
+
+            $filesExpected = count($state);
+            $filesFound = [];
+            $filesChanged = [];
+
+            foreach ($manifest->getFiles() as $file => $sum) {
+                // Unknown new file
+                if (!isset($state[$file])) {
+                    $filesChanged[] = $file;
+                    continue;
+                }
+
+                // Modified file
+                if ($state[$file] !== $sum) {
+                    $filesFound[] = $file;
+                    $filesChanged[] = $file;
+                    continue;
+                }
+
+                // Pristine file
+                $filesFound[] = $file;
+            }
+
+            $foundPercent = count($filesFound) / $filesExpected;
+            $changedPercent = count($filesChanged) / $filesExpected;
+
+            $score = ((1 * $foundPercent) - $changedPercent);
+            $buildMatch[$build] = round($score * 100, 2);
+        }
+
+
+        // Find likely version (we have to be at least 60% sure)
+        $likelyBuild = array_search(max($buildMatch), $buildMatch);
+        if ($buildMatch[$likelyBuild] < 60) {
+            return null;
+        }
+
+        return [
+            'build' => $likelyBuild,
+            'modified' => true,
+        ];
+    }
+
+    /**
+     * Determines file changes between the specified build and the previous build.
+     *
+     * Will return an array of added, modified and removed files.
+     *
+     * @param FileManifest $manifest The current build's file manifest.
+     * @param integer $previous The previous build number, used to determine changes with this build.
+     * @return array
+     */
+    protected function processChanges(FileManifest $manifest, $previous = null)
+    {
+        // If no previous build has been provided, all files are added
+        if (is_null($previous)) {
+            return [
+                'added' => $manifest->getFiles(),
+            ];
+        }
+
+        // Only save files if they are changing the "state" of the manifest (ie. the file is modified, added or removed)
+        $state = $this->getState($previous);
+        $added = [];
+        $modified = [];
+
+        foreach ($manifest->getFiles() as $file => $sum) {
+            if (!isset($state[$file])) {
+                $added[$file] = $sum;
+                continue;
+            } else {
+                if ($state[$file] !== $sum) {
+                    $modified[$file] = $sum;
+                }
+                unset($state[$file]);
+            }
+        }
+
+        // Any files still left in state have been removed
+        $removed = array_keys($state);
+
+        $changes = [];
+        if (count($added)) {
+            $changes['added'] = $added;
+        }
+        if (count($modified)) {
+            $changes['modified'] = $modified;
+        }
+        if (count($removed)) {
+            $changes['removed'] = $removed;
+        }
+
+        return $changes;
+    }
+}
diff --git a/modules/system/classes/UpdateManager.php b/modules/system/classes/UpdateManager.php
index 1b9c3618f..075bdafdc 100644
--- a/modules/system/classes/UpdateManager.php
+++ b/modules/system/classes/UpdateManager.php
@@ -358,23 +358,38 @@ class UpdateManager
     }
 
     /**
-     * Asks the gateway for the lastest build number and stores it.
+     * Determines build number from source manifest.
+     *
+     * An array will be returned with the following, if a build can be determined:
+     *  - `build` - The detected build number installed.
+     *  - `modified` - Whether the installation appears to have been modified.
+     *
+     * Otherwise, `null` will be returned.
+     *
+     * @return array|null
+     */
+    public function getBuildNumberManually()
+    {
+        $source = new SourceManifest();
+        $manifest = new FileManifest(null, null, true);
+
+        // Find build by comparing with source manifest
+        return $source->compare($manifest);
+    }
+
+    /**
+     * Sets the build number in the database.
+     *
      * @return void
      */
     public function setBuildNumberManually()
     {
-        $postData = [];
+        $build = $this->getBuildNumberManually();
 
-        if (Config::get('cms.edgeUpdates', false)) {
-            $postData['edge'] = 1;
+        if (!is_null($build)) {
+            $this->setBuild($build['build'], null, $build['modified']);
         }
 
-        $result = $this->requestServerData('ping', $postData);
-
-        $build = (int) array_get($result, 'pong', 420);
-
-        $this->setBuild($build);
-
         return $build;
     }
 
@@ -457,12 +472,14 @@ class UpdateManager
      * Sets the build number and hash
      * @param string $hash
      * @param string $build
+     * @param bool $modified
      * @return void
      */
-    public function setBuild($build, $hash = null)
+    public function setBuild($build, $hash = null, $modified = false)
     {
         $params = [
-            'system::core.build' => $build
+            'system::core.build' => $build,
+            'system::core.modified' => $modified,
         ];
 
         if ($hash) {
diff --git a/modules/system/console/OctoberManifest.php b/modules/system/console/OctoberManifest.php
new file mode 100644
index 000000000..b92db74a7
--- /dev/null
+++ b/modules/system/console/OctoberManifest.php
@@ -0,0 +1,170 @@
+<?php namespace System\Console;
+
+use ApplicationException;
+use ZipArchive;
+use System\Classes\FileManifest;
+use System\Classes\SourceManifest;
+
+class OctoberManifest extends \Illuminate\Console\Command
+{
+    /**
+     * @var string The console command description.
+     */
+    protected $description = 'Generates a build manifest of October CMS builds.';
+
+    /**
+     * @var string The name and signature of the console command.
+     */
+    protected $signature = 'october:manifest
+                            {target : Specifies the target file for the build manifest.}
+                            {--minBuild= : Specifies the minimum build number to retrieve from the source.}
+                            {--maxBuild= : Specifies the maximum build number to retreive from the source.}';
+
+    /**
+     * @var bool Indicates whether the command should be shown in the Artisan command list.
+     */
+    protected $hidden = true;
+
+    /**
+     * @var string Source repository download file.
+     */
+    protected $sourceBuildFile = 'https://github.com/octobercms/october/archive/v1.0.%d.zip';
+
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $minBuild = $this->option('minBuild') ?? 420;
+        $maxBuild = $this->option('maxBuild') ?? 9999;
+
+        $targetFile = (substr($this->argument('target'), 0, 1) === '/')
+            ? $this->argument('target')
+            : getcwd() . '/' . $this->argument('target');
+
+        if (empty($targetFile)) {
+            throw new ApplicationException(
+                'A target argument must be specified for the generated manifest file.'
+            );
+        }
+
+        if ($minBuild > $maxBuild) {
+            throw new ApplicationException(
+                'Minimum build specified is larger than the maximum build specified.'
+            );
+        }
+
+        if (file_exists($targetFile)) {
+            $manifest = new SourceManifest($targetFile);
+            $manifestMaxBuild = $manifest->getMaxBuild();
+
+            if ($manifestMaxBuild > $minBuild) {
+                $minBuild = $manifestMaxBuild + 1;
+
+                if ($minBuild > $maxBuild) {
+                    throw new ApplicationException(
+                        'This manifest already contains all requested builds.'
+                    );
+                }
+            }
+        } else {
+            $manifest = new SourceManifest('', false);
+        }
+
+        // Create temporary directory to hold builds
+        $buildDir = storage_path('temp/builds/');
+        if (!is_dir($buildDir)) {
+            mkdir($buildDir, 0775, true);
+        }
+
+        for ($build = $minBuild; $build <= $maxBuild; ++$build) {
+            // Download version from GitHub
+            $this->comment('Processing build ' . $build);
+            $this->line('  - Downloading...');
+
+            if (file_exists($buildDir . 'build-' . $build . '.zip') || is_dir($buildDir . $build . '/')) {
+                $this->info('  - Already downloaded.');
+            } else {
+                $zipUrl = sprintf($this->sourceBuildFile, $build);
+                $zipFile = @file_get_contents($zipUrl);
+
+                if (empty($zipFile)) {
+                    $this->error('  - Not found.');
+                    break;
+                }
+
+                file_put_contents($buildDir . 'build-' . $build . '.zip', $zipFile);
+
+                $this->info('  - Downloaded.');
+            }
+
+            // Extract version
+            $this->line('  - Extracting...');
+            if (is_dir($buildDir . $build . '/')) {
+                $this->info('  - Already extracted.');
+            } else {
+                $zip = new ZipArchive;
+                if ($zip->open($buildDir . 'build-' . $build . '.zip')) {
+                    $toExtract = [];
+                    $paths = [
+                        'october-1.0.' . $build . '/modules/backend/',
+                        'october-1.0.' . $build . '/modules/cms/',
+                        'october-1.0.' . $build . '/modules/system/',
+                    ];
+
+                    // Only get necessary files from the modules directory
+                    for ($i = 0; $i < $zip->numFiles; ++$i) {
+                        $filename = $zip->statIndex($i)['name'];
+
+                        foreach ($paths as $path) {
+                            if (strpos($filename, $path) === 0) {
+                                $toExtract[] = $filename;
+                                break;
+                            }
+                        }
+                    }
+
+                    if (!count($toExtract)) {
+                        $this->error('  - Unable to get valid files for extraction. Cancelled.');
+                        exit(1);
+                    }
+
+                    $zip->extractTo($buildDir . $build . '/', $toExtract);
+                    $zip->close();
+
+                    // Remove ZIP file
+                    unlink($buildDir . 'build-' . $build . '.zip');
+                } else {
+                    $this->error('  - Unable to extract zip file. Cancelled.');
+                    exit(1);
+                }
+
+                $this->info('  - Extracted.');
+            }
+
+            // Determine previous build
+            $manifestBuilds = $manifest->getBuilds();
+            $previous = null;
+            if (count($manifestBuilds)) {
+                if (isset($manifestBuilds[$build - 1])) {
+                    $previous = $build - 1;
+                }
+            }
+
+            // Add build to manifest
+            $this->line('  - Adding to manifest...');
+            $buildManifest = new FileManifest($buildDir . $build . '/october-1.0.' . $build);
+            $manifest->addBuild($build, $buildManifest, $previous);
+            $this->info('  - Added.');
+        }
+
+        // Generate manifest
+        $this->comment('Generating manifest...');
+        file_put_contents($targetFile, $manifest->generate());
+
+        $this->comment('Completed.');
+    }
+}
diff --git a/modules/system/console/OctoberUtil.php b/modules/system/console/OctoberUtil.php
index 9a886d665..14700a31f 100644
--- a/modules/system/console/OctoberUtil.php
+++ b/modules/system/console/OctoberUtil.php
@@ -1,6 +1,5 @@
 <?php namespace System\Console;
 
-use App;
 use Lang;
 use File;
 use Config;
@@ -9,7 +8,6 @@ use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Input\InputArgument;
 use System\Classes\UpdateManager;
 use System\Classes\CombineAssets;
-use Exception;
 use System\Models\Parameter;
 use System\Models\File as FileModel;
 
@@ -28,7 +26,6 @@ use System\Models\File as FileModel;
  * - compile less: Compile registered LESS files only.
  * - compile scss: Compile registered SCSS files only.
  * - compile lang: Compile registered Language files only.
- * - set build: Pull the latest stable build number from the update gateway and set it as the current build number.
  * - set project --projectId=<id>: Set the projectId for this october instance.
  *
  * @package october\system
@@ -111,31 +108,10 @@ class OctoberUtil extends Command
 
     protected function utilSetBuild()
     {
-        $this->comment('-');
+        $this->comment('NOTE: This command is now deprecated. Please use "php artisan october:version" instead.');
+        $this->comment('');
 
-        /*
-         * Skip setting the build number if no database is detected to set it within
-         */
-        if (!App::hasDatabase()) {
-            $this->comment('No database detected - skipping setting the build number.');
-            return;
-        }
-
-        try {
-            $build = UpdateManager::instance()->setBuildNumberManually();
-            $this->comment('*** October sets build: '.$build);
-        }
-        catch (Exception $ex) {
-            $this->comment('*** You were kicked from #october by Ex: ('.$ex->getMessage().')');
-        }
-
-        $this->comment('-');
-        sleep(1);
-        $this->comment('Ping? Pong!');
-        $this->comment('-');
-        sleep(1);
-        $this->comment('Ping? Pong!');
-        $this->comment('-');
+        return $this->call('october:version');
     }
 
     protected function utilCompileJs()
diff --git a/modules/system/console/OctoberVersion.php b/modules/system/console/OctoberVersion.php
new file mode 100644
index 000000000..95a809b58
--- /dev/null
+++ b/modules/system/console/OctoberVersion.php
@@ -0,0 +1,47 @@
+<?php namespace System\Console;
+
+use App;
+use System\Classes\UpdateManager;
+
+class OctoberVersion extends \Illuminate\Console\Command
+{
+    /**
+     * @var string The console command description.
+     */
+    protected $description = 'Detects the build number (version) of this October CMS instance.';
+
+    /**
+     * @var string The name and signature of the console command.
+     */
+    protected $signature = 'october:version';
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $this->comment('*** Detecting October CMS build...');
+
+        if (!App::hasDatabase()) {
+            $build = UpdateManager::instance()->getBuildNumberManually();
+
+            // Skip setting the build number if no database is detected to set it within
+            $this->comment('*** No database detected - skipping setting the build number.');
+        } else {
+            $build = UpdateManager::instance()->setBuildNumberManually();
+        }
+
+        if (is_null($build)) {
+            $this->error('Unable to detect your build of October CMS.');
+            return;
+        }
+
+        if ($build['modified']) {
+            $this->info('*** Detected a modified version of October CMS build ' . $build['build'] . '.');
+        } else {
+            $this->info('*** Detected October CMS build ' . $build['build'] . '.');
+        }
+    }
+}
diff --git a/modules/system/controllers/Updates.php b/modules/system/controllers/Updates.php
index ed66175d5..1d1be7923 100644
--- a/modules/system/controllers/Updates.php
+++ b/modules/system/controllers/Updates.php
@@ -75,6 +75,7 @@ class Updates extends Controller
     public function index()
     {
         $this->vars['coreBuild'] = Parameter::get('system::core.build');
+        $this->vars['coreBuildModified'] = Parameter::get('system::core.modified', false);
         $this->vars['projectId'] = Parameter::get('system::project.id');
         $this->vars['projectName'] = Parameter::get('system::project.name');
         $this->vars['projectOwner'] = Parameter::get('system::project.owner');
diff --git a/modules/system/controllers/updates/index.htm b/modules/system/controllers/updates/index.htm
index f59abe07c..64f2b831a 100644
--- a/modules/system/controllers/updates/index.htm
+++ b/modules/system/controllers/updates/index.htm
@@ -34,7 +34,19 @@
         <?php if ($coreBuild): ?>
             <div class="scoreboard-item title-value">
                 <h4><?= e(trans('system::lang.updates.core_current_build')) ?></h4>
-                <p><?= $coreBuild ?></p>
+                <?php if ($coreBuildModified): ?>
+                    <p
+                        class="oc-icon-exclamation-circle"
+                        data-toggle="tooltip"
+                        data-placement="bottom"
+                        title="This build has been modified"
+                    >
+                        <?= $coreBuild ?>
+                    </p>
+                <?php else: ?>
+                    <p><?= $coreBuild ?></p>
+                <?php endif; ?>
+
                 <p class="description">
                     <a
                         href="javascript:;"
diff --git a/tests/fixtures/manifest/1/modules/test/file1.php b/tests/fixtures/manifest/1/modules/test/file1.php
new file mode 100644
index 000000000..008f7f320
--- /dev/null
+++ b/tests/fixtures/manifest/1/modules/test/file1.php
@@ -0,0 +1,2 @@
+<?php
+// file1.php - version 1.
diff --git a/tests/fixtures/manifest/2/modules/test/file1.php b/tests/fixtures/manifest/2/modules/test/file1.php
new file mode 100644
index 000000000..008f7f320
--- /dev/null
+++ b/tests/fixtures/manifest/2/modules/test/file1.php
@@ -0,0 +1,2 @@
+<?php
+// file1.php - version 1.
diff --git a/tests/fixtures/manifest/2/modules/test/file2.php b/tests/fixtures/manifest/2/modules/test/file2.php
new file mode 100644
index 000000000..9dd296bb3
--- /dev/null
+++ b/tests/fixtures/manifest/2/modules/test/file2.php
@@ -0,0 +1,2 @@
+<?php
+// file2.php - version 1.
diff --git a/tests/fixtures/manifest/2/modules/test2/file1.php b/tests/fixtures/manifest/2/modules/test2/file1.php
new file mode 100644
index 000000000..27f3bb12d
--- /dev/null
+++ b/tests/fixtures/manifest/2/modules/test2/file1.php
@@ -0,0 +1,2 @@
+<?php
+// file1.php - version 1 / test2.
diff --git a/tests/fixtures/manifest/3/modules/test/file2.php b/tests/fixtures/manifest/3/modules/test/file2.php
new file mode 100644
index 000000000..b30552533
--- /dev/null
+++ b/tests/fixtures/manifest/3/modules/test/file2.php
@@ -0,0 +1,2 @@
+<?php
+// file2.php - version 2.
diff --git a/tests/fixtures/manifest/3/modules/test/file3.php b/tests/fixtures/manifest/3/modules/test/file3.php
new file mode 100644
index 000000000..b98c74257
--- /dev/null
+++ b/tests/fixtures/manifest/3/modules/test/file3.php
@@ -0,0 +1,2 @@
+<?php
+// file3.php - version 1.
diff --git a/tests/fixtures/manifest/3/modules/test2/file1.php b/tests/fixtures/manifest/3/modules/test2/file1.php
new file mode 100644
index 000000000..27f3bb12d
--- /dev/null
+++ b/tests/fixtures/manifest/3/modules/test2/file1.php
@@ -0,0 +1,2 @@
+<?php
+// file1.php - version 1 / test2.
diff --git a/tests/unit/system/classes/FileManifestTest.php b/tests/unit/system/classes/FileManifestTest.php
new file mode 100644
index 000000000..a7246e2af
--- /dev/null
+++ b/tests/unit/system/classes/FileManifestTest.php
@@ -0,0 +1,58 @@
+<?php
+
+use October\Rain\Exception\ApplicationException;
+use System\Classes\FileManifest;
+
+class FileManifestTest extends TestCase
+{
+    /** @var FileManifest instance */
+    protected $fileManifest;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->fileManifest = new FileManifest(base_path('tests/fixtures/manifest/2'), ['test', 'test2']);
+    }
+
+    public function testGetFiles()
+    {
+        $this->assertEquals([
+            '/modules/test/file1.php' => '6f9b0b94528a85b2a6bb67b5621e074aef1b4c9fc9ee3ea1bd69100ea14cb3db',
+            '/modules/test/file2.php' => '96ae9f6b6377ad29226ea169f952de49fc29ae895f18a2caed76aeabdf050f1b',
+            '/modules/test2/file1.php' => '94bd47b1ac7b2837b31883ebcd38c8101687321f497c3c4b9744f68ae846721d',
+        ], $this->fileManifest->getFiles());
+    }
+
+    public function testGetModuleChecksums()
+    {
+        $this->assertEquals([
+            'test' => 'c0b794ff210862a4ce16223802efe6e28969f5a4fb42480ec8c2fef2da23d181',
+            'test2' => '32c9f2fb6e0a22dde288a0fe1e4834798360b25e5a91d2597409d9302221381d',
+        ], $this->fileManifest->getModuleChecksums());
+    }
+
+    public function testGetFilesInvalidRoot()
+    {
+        $this->expectException(ApplicationException::class);
+        $this->expectExceptionMessage('Invalid root specified for the file manifest.');
+
+        $this->fileManifest->setRoot(base_path('tests/fixtures/manifest/invalid'));
+
+        $this->fileManifest->getFiles();
+    }
+
+    public function testSingleModule()
+    {
+        $this->fileManifest->setModules(['test']);
+
+        $this->assertEquals([
+            '/modules/test/file1.php' => '6f9b0b94528a85b2a6bb67b5621e074aef1b4c9fc9ee3ea1bd69100ea14cb3db',
+            '/modules/test/file2.php' => '96ae9f6b6377ad29226ea169f952de49fc29ae895f18a2caed76aeabdf050f1b',
+        ], $this->fileManifest->getFiles());
+
+        $this->assertEquals([
+            'test' => 'c0b794ff210862a4ce16223802efe6e28969f5a4fb42480ec8c2fef2da23d181',
+        ], $this->fileManifest->getModuleChecksums());
+    }
+}
diff --git a/tests/unit/system/classes/SourceManifestTest.php b/tests/unit/system/classes/SourceManifestTest.php
new file mode 100644
index 000000000..9d5e7a783
--- /dev/null
+++ b/tests/unit/system/classes/SourceManifestTest.php
@@ -0,0 +1,194 @@
+<?php
+
+use October\Rain\Exception\ApplicationException;
+use System\Classes\SourceManifest;
+use System\Classes\FileManifest;
+
+class SourceManifestTest extends TestCase
+{
+    /** @var SourceManifest instance */
+    protected $sourceManifest;
+
+    /** @var array Emulated builds from the manifest fixture */
+    protected $builds;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->builds = [
+            1 => new FileManifest(base_path('tests/fixtures/manifest/1'), ['test', 'test2']),
+            2 => new FileManifest(base_path('tests/fixtures/manifest/2'), ['test', 'test2']),
+            3 => new FileManifest(base_path('tests/fixtures/manifest/3'), ['test', 'test2']),
+        ];
+
+        $this->sourceManifest = new SourceManifest($this->manifestPath(), false);
+    }
+
+    public function tearDown(): void
+    {
+        $this->deleteManifest();
+    }
+
+    public function testCreateManifest()
+    {
+        $this->createManifest(true);
+
+        $this->assertEquals(
+            '{' . "\n" .
+            '    "manifest": [' . "\n" .
+            '        {' . "\n" .
+            '            "build": 1,' . "\n" .
+            '            "modules": {' . "\n" .
+            '                "test": "e1d6c6e4c482688e231ee37d89668268426512013695de47bfcb424f9a645c7b",' . "\n" .
+            '                "test2": "a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a"' . "\n" .
+            '            },' . "\n" .
+            '            "files": {' . "\n" .
+            '                "added": {' . "\n" .
+            '                    "\/modules\/test\/file1.php": "6f9b0b94528a85b2a6bb67b5621e074aef1b4c9fc9ee3ea1bd69100ea14cb3db"' . "\n" .
+            '                }' . "\n" .
+            '            }' . "\n" .
+            '        },' . "\n" .
+            '        {' . "\n" .
+            '            "build": 2,' . "\n" .
+            '            "modules": {' . "\n" .
+            '                "test": "c0b794ff210862a4ce16223802efe6e28969f5a4fb42480ec8c2fef2da23d181",' . "\n" .
+            '                "test2": "32c9f2fb6e0a22dde288a0fe1e4834798360b25e5a91d2597409d9302221381d"' . "\n" .
+            '            },' . "\n" .
+            '            "files": {' . "\n" .
+            '                "added": {' . "\n" .
+            '                    "\/modules\/test\/file2.php": "96ae9f6b6377ad29226ea169f952de49fc29ae895f18a2caed76aeabdf050f1b",' . "\n" .
+            '                    "\/modules\/test2\/file1.php": "94bd47b1ac7b2837b31883ebcd38c8101687321f497c3c4b9744f68ae846721d"' . "\n" .
+            '                }' . "\n" .
+            '            }' . "\n" .
+            '        },' . "\n" .
+            '        {' . "\n" .
+            '            "build": 3,' . "\n" .
+            '            "modules": {' . "\n" .
+            '                "test": "419a3c073a4296213cdc9319cfc488383753e2e81cefa1c73db38749b82a3c51",' . "\n" .
+            '                "test2": "32c9f2fb6e0a22dde288a0fe1e4834798360b25e5a91d2597409d9302221381d"' . "\n" .
+            '            },' . "\n" .
+            '            "files": {' . "\n" .
+            '                "added": {' . "\n" .
+            '                    "\/modules\/test\/file3.php": "7f4132b05911a6b0df4d41bf5dc3d007786b63a5a22daf3060ed222816d57b54"' . "\n" .
+            '                },' . "\n" .
+            '                "modified": {' . "\n" .
+            '                    "\/modules\/test\/file2.php": "2c61b2f5688275574251a19a57e06a4eb9e537b3916ebf6f71768e184a4ae538"' . "\n" .
+            '                },' . "\n" .
+            '                "removed": [' . "\n" .
+            '                    "\/modules\/test\/file1.php"' . "\n" .
+            '                ]' . "\n" .
+            '            }' . "\n" .
+            '        }' . "\n" .
+            '    ]' . "\n" .
+            '}',
+            file_get_contents($this->manifestPath())
+        );
+    }
+
+    public function testGetBuilds()
+    {
+        $this->createManifest();
+
+        $buildKeys = array_keys($this->sourceManifest->getBuilds());
+
+        $this->assertCount(3, $buildKeys);
+        $this->assertEquals([1, 2, 3], $buildKeys);
+    }
+
+    public function testGetMaxBuild()
+    {
+        $this->createManifest();
+
+        $this->assertEquals(3, $this->sourceManifest->getMaxBuild());
+    }
+
+    public function testGetState()
+    {
+        $this->createManifest();
+
+        $this->assertEquals([
+            '/modules/test/file1.php' => '6f9b0b94528a85b2a6bb67b5621e074aef1b4c9fc9ee3ea1bd69100ea14cb3db',
+        ], $this->sourceManifest->getState(1));
+
+        $this->assertEquals([
+            '/modules/test/file1.php' => '6f9b0b94528a85b2a6bb67b5621e074aef1b4c9fc9ee3ea1bd69100ea14cb3db',
+            '/modules/test/file2.php' => '96ae9f6b6377ad29226ea169f952de49fc29ae895f18a2caed76aeabdf050f1b',
+            '/modules/test2/file1.php' => '94bd47b1ac7b2837b31883ebcd38c8101687321f497c3c4b9744f68ae846721d',
+        ], $this->sourceManifest->getState(2));
+
+        $this->assertEquals([
+            '/modules/test/file2.php' => '2c61b2f5688275574251a19a57e06a4eb9e537b3916ebf6f71768e184a4ae538',
+            '/modules/test/file3.php' => '7f4132b05911a6b0df4d41bf5dc3d007786b63a5a22daf3060ed222816d57b54',
+            '/modules/test2/file1.php' => '94bd47b1ac7b2837b31883ebcd38c8101687321f497c3c4b9744f68ae846721d',
+        ], $this->sourceManifest->getState(3));
+    }
+
+    public function testCompare()
+    {
+        $this->createManifest();
+
+        $this->assertEquals([
+            'build' => 1,
+            'modified' => false,
+        ], $this->sourceManifest->compare($this->builds[1]));
+
+        $this->assertEquals([
+            'build' => 2,
+            'modified' => false,
+        ], $this->sourceManifest->compare($this->builds[2]));
+
+        $this->assertEquals([
+            'build' => 3,
+            'modified' => false,
+        ], $this->sourceManifest->compare($this->builds[3]));
+    }
+
+    public function testCompareModified()
+    {
+        $this->createManifest();
+
+        // Hot-swap "tests/fixtures/manifest/3/modules/test/file3.php"
+        $old = file_get_contents(base_path('tests/fixtures/manifest/3/modules/test/file3.php'));
+        file_put_contents(base_path('tests/fixtures/manifest/3/modules/test/file3.php'), '<?php // Changed');
+
+        $modifiedManifest = new FileManifest(base_path('tests/fixtures/manifest/3'), ['test', 'test2']);
+        $modifiedManifest->getFiles();
+
+        file_put_contents(base_path('tests/fixtures/manifest/3/modules/test/file3.php'), $old);
+
+        $this->assertEquals([
+            'build' => 3,
+            'modified' => true,
+        ], $this->sourceManifest->compare($modifiedManifest));
+    }
+
+    protected function createManifest(bool $write = false)
+    {
+        $this->deleteManifest();
+
+        $last = null;
+
+        foreach ($this->builds as $build => $fileManifest) {
+            $this->sourceManifest->addBuild($build, $fileManifest, $last);
+
+            $last = $build;
+        }
+
+        if ($write) {
+            file_put_contents($this->manifestPath(), $this->sourceManifest->generate());
+        }
+    }
+
+    protected function deleteManifest()
+    {
+        if (file_exists($this->manifestPath())) {
+            unlink($this->manifestPath());
+        }
+    }
+
+    protected function manifestPath()
+    {
+        return base_path('tests/fixtures/manifest/builds.json');
+    }
+}