diff --git a/.github/workflows/php-test.yml b/.github/workflows/php-test.yml
index d2c1bd6..0d2eeae 100644
--- a/.github/workflows/php-test.yml
+++ b/.github/workflows/php-test.yml
@@ -89,5 +89,5 @@ jobs:
         run: composer install
 
       - name: Run PHPStan
-        run: ./vendor/bin/phpstan analyse lib -l1
+        run: ./vendor/bin/phpstan analyse lib -l5
 
diff --git a/lib/FailureHandler.php b/lib/FailureHandler.php
index c2c2038..8c7c78c 100644
--- a/lib/FailureHandler.php
+++ b/lib/FailureHandler.php
@@ -23,8 +23,8 @@ class FailureHandler
 	/**
 	 * Create a new failed job on the backend.
 	 *
-	 * @param object $payload        The contents of the job that has just failed.
-	 * @param \Exception $exception  The exception generated when the job failed to run.
+	 * @param object|array                $payload        The contents of the job that has just failed.
+	 * @param \Exception                  $exception  The exception generated when the job failed to run.
 	 * @param \Resque\Worker\ResqueWorker $worker Instance of Resque\Worker\ResqueWorker
 	 *											  that was running this job when it failed.
 	 * @param string $queue          The name of the queue that this job was fetched from.
@@ -38,8 +38,8 @@ public static function create($payload, Exception $exception, ResqueWorker $work
 	/**
 	 * Create a new failed job on the backend from PHP 7 errors.
 	 *
-	 * @param object $payload        The contents of the job that has just failed.
-	 * @param \Error $exception  The PHP 7 error generated when the job failed to run.
+	 * @param object|array $payload               The contents of the job that has just failed.
+	 * @param \Error       $exception             The PHP 7 error generated when the job failed to run.
 	 * @param \Resque\Worker\ResqueWorker $worker Instance of Resque\Worker\ResqueWorker
 	 *											  that was running this job when it failed.
 	 * @param string $queue          The name of the queue that this job was fetched from.
@@ -53,7 +53,7 @@ public static function createFromError($payload, Error $exception, ResqueWorker
 	/**
 	 * Return an instance of the backend for saving job failures.
 	 *
-	 * @return object Instance of backend object.
+	 * @return object|string Instance of backend object.
 	 */
 	public static function getBackend()
 	{
diff --git a/lib/Job/Factory.php b/lib/Job/Factory.php
index 05b0bf6..10228da 100644
--- a/lib/Job/Factory.php
+++ b/lib/Job/Factory.php
@@ -7,9 +7,10 @@
 class Factory implements FactoryInterface
 {
 	/**
-	 * @param $className
-	 * @param array $args
-	 * @param $queue
+	 * @param class-string<\Resque\Job\Job> $className
+	 * @param array        							 $args
+	 * @param string       							 $queue
+	 *
 	 * @return \Resque\Job\Job
 	 * @throws \Resque\Exceptions\ResqueException
 	 */
diff --git a/lib/Job/Status.php b/lib/Job/Status.php
index acfdf52..2348bfd 100644
--- a/lib/Job/Status.php
+++ b/lib/Job/Status.php
@@ -97,7 +97,8 @@ public function isTracking()
 	/**
 	 * Update the status indicator for the current job with a new status.
 	 *
-	 * @param int The status of the job (see constants in Resque\Job\Status)
+	 * @param int 	$status The status of the job (see constants in Resque\Job\Status)
+	 * @param mixed $result The result of the job
 	 */
 	public function update($status, $result = null)
 	{
diff --git a/lib/JobHandler.php b/lib/JobHandler.php
index a6d2cef..a255632 100755
--- a/lib/JobHandler.php
+++ b/lib/JobHandler.php
@@ -5,6 +5,7 @@
 use Resque\Job\PID;
 use Resque\Job\Status;
 use Resque\Exceptions\DoNotPerformException;
+use Resque\Exceptions\ResqueException;
 use Resque\Job\FactoryInterface;
 use Resque\Job\Factory;
 use Resque\Job\Job;
@@ -25,7 +26,7 @@ class JobHandler
 	public $queue;
 
 	/**
-	 * @var \Resque\Worker\Resque Instance of the Resque worker running this job.
+	 * @var \Resque\Worker\ResqueWorker Instance of the Resque worker running this job.
 	 */
 	public $worker;
 
@@ -79,12 +80,12 @@ public function __construct($queue, $payload)
 	/**
 	 * Create a new job and save it to the specified queue.
 	 *
-	 * @param string $queue The name of the queue to place the job in.
-	 * @param string $class The name of the class that contains the code to execute the job.
-	 * @param array $args Any optional arguments that should be passed when the job is executed.
-	 * @param boolean $monitor Set to true to be able to monitor the status of a job.
-	 * @param string $id Unique identifier for tracking the job. Generated if not supplied.
-	 * @param string $prefix The prefix needs to be set for the status key
+	 * @param string 	   		$queue   The name of the queue to place the job in.
+	 * @param class-string<Job> $class   The name of the class that contains the code to execute the job.
+	 * @param array        		$args    Any optional arguments that should be passed when the job is executed.
+	 * @param boolean 	   		$monitor Set to true to be able to monitor the status of a job.
+	 * @param string 	   		$id      Unique identifier for tracking the job. Generated if not supplied.
+	 * @param string 	   		$prefix  The prefix needs to be set for the status key
 	 *
 	 * @return string
 	 */
@@ -192,16 +193,17 @@ public function getArguments(): array
 
 	/**
 	 * Get the instantiated object for this job that will be performing work.
-	 * @return \Resque\Job\Job Instance of the object that this job belongs to.
-	 * @throws \Resque\Exceptions\ResqueException
+	 * @return Job Instance of the object that this job belongs to.
+	 * @throws ResqueException
 	 */
 	public function getInstance(): Job
 	{
-		if (!is_null($this->instance)) {
+		if (isset($this->instance)) {
 			return $this->instance;
 		}
 
-		$this->instance = $this->getJobFactory()->create($this->payload['class'], $this->getArguments(), $this->queue);
+		$this->instance = $this->getJobFactory()
+							   ->create($this->payload['class'], $this->getArguments(), $this->queue);
 		$this->instance->job = $this;
 		$this->instance->jobID = $this->payload['id'];
 		return $this->instance;
@@ -211,8 +213,8 @@ public function getInstance(): Job
 	 * Actually execute a job by calling the perform method on the class
 	 * associated with the job with the supplied arguments.
 	 *
-	 * @return mixed
-	 * @throws Resque\Exceptions\ResqueException When the job's class could not be found.
+	 * @return mixed Return of perform, or false if DoNotPerformException was thrown
+	 * @throws ResqueException When the job's class could not be found.
 	 */
 	public function perform()
 	{
@@ -325,8 +327,8 @@ public function __toString()
 	}
 
 	/**
-	 * @param Resque\Job\FactoryInterface $jobFactory
-	 * @return Resque\JobHandler
+	 * @param \Resque\Job\FactoryInterface $jobFactory
+	 * @return \Resque\JobHandler
 	 */
 	public function setJobFactory(FactoryInterface $jobFactory)
 	{
@@ -336,7 +338,7 @@ public function setJobFactory(FactoryInterface $jobFactory)
 	}
 
 	/**
-	 * @return Resque\Job\FactoryInterface
+	 * @return \Resque\Job\FactoryInterface
 	 */
 	public function getJobFactory(): FactoryInterface
 	{
diff --git a/lib/Redis.php b/lib/Redis.php
index 8378e2b..35c1288 100644
--- a/lib/Redis.php
+++ b/lib/Redis.php
@@ -15,7 +15,7 @@
  * @author		Chris Boulton <chris@bigcommerce.com>
  * @license		http://www.opensource.org/licenses/mit-license.php
  *
- * @method array|null    blpop(string $keyN, int $timeout)
+ * @method array|null    blpop(string|string[] $keyN, int $timeout)
  * @method int           decrby(string $key, int $decrement)
  * @method int           del(string|array ...$keys)
  * @method int           exists(string $key)
@@ -27,7 +27,7 @@
  * @method string|null   lpop(string $key)
  * @method array         lrange(string $key, int $start, int $stop)
  * @method int           lrem(string $key, int $count, mixed $value)
- * @method string        ping(string|null $name = null)
+ * @method string|bool   ping(string|null $name = null)
  * @method string|null   rpop(string $key)
  * @method string|null   rpoplpush(string $source, string $destination)
  * @method int           rpush(string $key, mixed $value, mixed $valueN = null)
@@ -146,7 +146,7 @@ public static function prefix($namespace)
 	}
 
 	/**
-	 * @param string|array $server A DSN or array
+	 * @param string|array|object $server A DSN or array
 	 * @param int $database A database number to select. However, if we find a valid database number in the DSN the
 	 *                      DSN-supplied value will be used instead and this parameter is ignored.
 	 * @param object $client Optional Credis_Cluster or Credis_Client instance instantiated by you
diff --git a/lib/Resque.php b/lib/Resque.php
index 384dfec..cc18fad 100644
--- a/lib/Resque.php
+++ b/lib/Resque.php
@@ -19,7 +19,7 @@ class Resque
 	public const DEFAULT_INTERVAL = 5;
 
 	/**
-	 * @var Redis Instance of Resque\Redis that talks to redis.
+	 * @var Redis|null Instance of Resque\Redis that talks to redis.
 	 */
 	public static $redis = null;
 
@@ -89,7 +89,7 @@ public static function redis()
 	 *
 	 * Will close connection to Redis before forking.
 	 *
-	 * @return int Return vars as per pcntl_fork(). False if pcntl_fork is unavailable
+	 * @return int|false Return vars as per pcntl_fork(). False if pcntl_fork is unavailable
 	 */
 	public static function fork()
 	{
@@ -135,14 +135,14 @@ public static function push($queue, $item)
 	 * return it.
 	 *
 	 * @param string $queue The name of the queue to fetch an item from.
-	 * @return array Decoded item from the queue.
+	 * @return array|null Decoded item from the queue.
 	 */
 	public static function pop($queue)
 	{
 		$item = self::redis()->lpop('queue:' . $queue);
 
 		if (!$item) {
-			return;
+			return null;
 		}
 
 		return json_decode($item, true);
@@ -195,7 +195,7 @@ public static function blpop(array $queues, $timeout)
 		$item = self::redis()->blpop($list, (int)$timeout);
 
 		if (!$item) {
-			return;
+			return null;
 		}
 
 		/**
diff --git a/lib/Scheduler.php b/lib/Scheduler.php
index edc3777..2d49c6f 100644
--- a/lib/Scheduler.php
+++ b/lib/Scheduler.php
@@ -73,7 +73,7 @@ public static function delayedPush($timestamp, $item)
 		$redis = Resque::redis();
 		$redis->rpush('delayed:' . $timestamp, json_encode($item));
 
-		$redis->zadd('delayed_queue_schedule', $timestamp, $timestamp);
+		$redis->zadd('delayed_queue_schedule', $timestamp, (string) $timestamp);
 	}
 
 	/**
@@ -95,7 +95,7 @@ public static function getDelayedQueueScheduleSize()
 	public static function getDelayedTimestampSize($timestamp)
 	{
 		$timestamp = self::getTimestamp($timestamp);
-		return Resque::redis()->llen('delayed:' . $timestamp, $timestamp);
+		return Resque::redis()->llen('delayed:' . $timestamp);
 	}
 
 	/**
@@ -184,7 +184,7 @@ private static function cleanupTimestamp($key, $timestamp)
 
 		if ($redis->llen($key) == 0) {
 			$redis->del($key);
-			$redis->zrem('delayed_queue_schedule', $timestamp);
+			$redis->zrem('delayed_queue_schedule', (string) $timestamp);
 		}
 	}
 
@@ -193,7 +193,7 @@ private static function cleanupTimestamp($key, $timestamp)
 	 *
 	 * @param \DateTime|int $timestamp Instance of DateTime or UNIX timestamp.
 	 * @return int Timestamp
-	 * @throws Scheduler_InvalidTimestampException
+	 * @throws InvalidTimestampException
 	 */
 	private static function getTimestamp($timestamp)
 	{
@@ -218,8 +218,8 @@ private static function getTimestamp($timestamp)
 	 * that any jobs scheduled for the past when the worker wasn't running are
 	 * also queued up.
 	 *
-	 * @param \DateTime|int $timestamp Instance of DateTime or UNIX timestamp.
-	 *                                Defaults to now.
+	 * @param \DateTime|int $at Instance of DateTime or UNIX timestamp.
+	 *                          Defaults to now.
 	 * @return int|false UNIX timestamp, or false if nothing to run.
 	 */
 	public static function nextDelayedTimestamp($at = null)
diff --git a/lib/Worker/ResqueWorker.php b/lib/Worker/ResqueWorker.php
index d400f72..f09ce40 100644
--- a/lib/Worker/ResqueWorker.php
+++ b/lib/Worker/ResqueWorker.php
@@ -69,12 +69,12 @@ class ResqueWorker
 	private $id;
 
 	/**
-	 * @var \Resque\JobHandler Current job, if any, being processed by this worker.
+	 * @var \Resque\JobHandler|null Current job, if any, being processed by this worker.
 	 */
 	private $currentJob = null;
 
 	/**
-	 * @var int Process ID of child worker processes.
+	 * @var int|null Process ID of child worker processes.
 	 */
 	private $child = null;
 
@@ -145,7 +145,7 @@ public static function exists($workerId)
 	 * Given a worker ID, find it and return an instantiated worker class for it.
 	 *
 	 * @param string $workerId The ID of the worker.
-	 * @return \Resque\Worker\ResqueWorker Instance of the worker. False if the worker does not exist.
+	 * @return \Resque\Worker\ResqueWorker|false Instance of the worker. False if the worker does not exist.
 	 */
 	public static function find($workerId)
 	{
@@ -338,7 +338,7 @@ public function perform(JobHandler $job)
 	/**
 	 * @param  bool            $blocking
 	 * @param  int             $timeout
-	 * @return object|boolean               Instance of Resque\JobHandler if a job is found, false if not.
+	 * @return \Resque\JobHandler|boolean Instance of Resque\JobHandler if a job is found, false if not.
 	 */
 	public function reserve($blocking = false, $timeout = null)
 	{
@@ -349,7 +349,7 @@ public function reserve($blocking = false, $timeout = null)
 
 		$queues = $this->queues();
 		if (!is_array($queues)) {
-			return;
+			return false;
 		}
 
 		if ($blocking === true) {
@@ -423,7 +423,7 @@ private function startup()
 	 */
 	private function updateProcLine($status)
 	{
-		$processTitle  = static::$processPrefix . '-' . Resque::VERSION;
+		$processTitle  = self::$processPrefix . '-' . Resque::VERSION;
 		$processTitle .= ' (' . implode(',', $this->queues) . '): ' . $status;
 		if (function_exists('cli_set_process_title') && PHP_OS !== 'Darwin') {
 			cli_set_process_title($processTitle);
@@ -605,7 +605,7 @@ public function unregisterWorker()
 	/**
 	 * Tell Redis which job we're currently working on.
 	 *
-	 * @param object $job \Resque\JobHandler instance containing the job we're working on.
+	 * @param \Resque\JobHandler $job instance containing the job we're working on.
 	 */
 	public function workingOn(JobHandler $job)
 	{
@@ -645,7 +645,7 @@ public function __toString()
 	/**
 	 * Return an object describing the job this worker is currently working on.
 	 *
-	 * @return object Object with details of current job.
+	 * @return array<string, mixed> Object with details of current job.
 	 */
 	public function job()
 	{