diff --git a/src/AddressList.php b/src/AddressList.php
index 2a1cd16f..f34e7c5d 100644
--- a/src/AddressList.php
+++ b/src/AddressList.php
@@ -111,7 +111,6 @@ public function addFromString($address, $comment = null)
     /**
      * Merge another address list into this one
      *
-     * @param  AddressList $addressList
      * @return AddressList
      */
     public function merge(self $addressList)
diff --git a/src/Header/AbstractAddressList.php b/src/Header/AbstractAddressList.php
index 0e66cb31..11a9a758 100644
--- a/src/Header/AbstractAddressList.php
+++ b/src/Header/AbstractAddressList.php
@@ -15,8 +15,8 @@
 use function preg_match_all;
 use function preg_replace;
 use function sprintf;
+use function str_contains;
 use function str_replace;
-use function strpos;
 use function strtolower;
 use function trim;
 
@@ -94,16 +94,13 @@ public static function fromString($headerLine)
 
         $wasEncoded = false;
         $addresses  = array_map(
-            function ($value) use (&$wasEncoded) {
+            static function ($value) use (&$wasEncoded): ?Address {
                 $decodedValue = HeaderWrap::mimeDecodeValue($value);
                 $wasEncoded   = $wasEncoded || ($decodedValue !== $value);
-
-                $value = trim($decodedValue);
-
-                $comments = self::getComments($value);
-                $value    = self::stripComments($value);
-
-                $value = preg_replace(
+                $value        = trim($decodedValue);
+                $comments     = self::getComments($value);
+                $value        = self::stripComments($value);
+                $value        = preg_replace(
                     [
                         '#(?<!\\\)"(.*)(?<!\\\)"#', // quoted-text
                         '#\\\([\x01-\x09\x0b\x0c\x0e-\x7f])#', // quoted-pair
@@ -114,7 +111,6 @@ function ($value) use (&$wasEncoded) {
                     ],
                     $value
                 );
-
                 return empty($value) ? null : Address::fromString($value, $comments);
             },
             $values
@@ -183,7 +179,7 @@ public function getFieldValue($format = HeaderInterface::FORMAT_RAW)
             $name  = $address->getName();
 
             // quote $name if value requires so
-            if (! empty($name) && (false !== strpos($name, ',') || false !== strpos($name, ';'))) {
+            if (! empty($name) && (str_contains($name, ',') || str_contains($name, ';'))) {
                 // FIXME: what if name contains double quote?
                 $name = sprintf('"%s"', $name);
             }
diff --git a/src/Header/HeaderLocator.php b/src/Header/HeaderLocator.php
index 7420cf17..aea47759 100644
--- a/src/Header/HeaderLocator.php
+++ b/src/Header/HeaderLocator.php
@@ -12,7 +12,7 @@
 final class HeaderLocator implements HeaderLocatorInterface
 {
     /** @var array Pre-aliased Header plugins */
-    private $plugins = [
+    private array $plugins = [
         'bcc'                       => Bcc::class,
         'cc'                        => Cc::class,
         'contentdisposition'        => ContentDisposition::class,
diff --git a/src/Header/HeaderWrap.php b/src/Header/HeaderWrap.php
index f33e0633..46163012 100644
--- a/src/Header/HeaderWrap.php
+++ b/src/Header/HeaderWrap.php
@@ -11,6 +11,8 @@
 use function iconv_mime_decode;
 use function iconv_mime_encode;
 use function implode;
+use function str_contains;
+use function str_starts_with;
 use function strlen;
 use function strpos;
 use function wordwrap;
@@ -119,9 +121,7 @@ public static function mimeDecodeValue($value)
         if (self::isNotDecoded($value, $decodedValue) && extension_loaded('imap')) {
             return array_reduce(
                 imap_mime_header_decode(imap_utf8($value)),
-                function ($accumulator, $headerPart) {
-                    return $accumulator . $headerPart->text;
-                },
+                static fn($accumulator, $headerPart) => $accumulator . $headerPart->text,
                 ''
             );
         }
@@ -131,9 +131,9 @@ function ($accumulator, $headerPart) {
 
     private static function isNotDecoded(string $originalValue, string $value): bool
     {
-        return 0 === strpos($value, '=?')
+        return str_starts_with($value, '=?')
             && strlen($value) - 2 === strpos($value, '?=')
-            && false !== strpos($originalValue, $value);
+            && str_contains($originalValue, $value);
     }
 
     /**
diff --git a/src/Header/IdentificationField.php b/src/Header/IdentificationField.php
index b8664120..79fd2e42 100644
--- a/src/Header/IdentificationField.php
+++ b/src/Header/IdentificationField.php
@@ -76,9 +76,7 @@ public function getFieldName()
      */
     public function getFieldValue($format = HeaderInterface::FORMAT_RAW)
     {
-        return implode(Headers::FOLDING, array_map(function ($id) {
-            return sprintf('<%s>', $id);
-        }, $this->messageIds));
+        return implode(Headers::FOLDING, array_map(static fn($id) => sprintf('<%s>', $id), $this->messageIds));
     }
 
     /**
diff --git a/src/Headers.php b/src/Headers.php
index 3e516639..36832e1b 100644
--- a/src/Headers.php
+++ b/src/Headers.php
@@ -10,11 +10,13 @@
 use Laminas\Loader\PluginClassLocator;
 use Laminas\Mail\Header\GenericHeader;
 use Laminas\Mail\Header\HeaderInterface;
+use Laminas\Mail\Header\HeaderLocatorInterface;
 use ReturnTypeWillChange;
 use Traversable;
 
 use function array_keys;
 use function array_shift;
+use function assert;
 use function count;
 use function current;
 use function explode;
@@ -49,8 +51,7 @@ class Headers implements Countable, Iterator
     /** @var string Start of Line when folding */
     public const FOLDING = "\r\n ";
 
-    /** @var null|Header\HeaderLocatorInterface */
-    private $headerLocator;
+    private ?HeaderLocatorInterface $headerLocator = null;
 
     /**
      * @todo Remove for 3.0.0.
@@ -193,11 +194,14 @@ public function getPluginClassLoader()
      *
      * Lazyloads a Header\HeaderLocator instance if necessary.
      */
-    public function getHeaderLocator(): Header\HeaderLocatorInterface
+    public function getHeaderLocator(): HeaderLocatorInterface
     {
         if (! $this->headerLocator) {
             $this->setHeaderLocator(new Header\HeaderLocator());
         }
+
+        assert($this->headerLocator instanceof HeaderLocatorInterface);
+
         return $this->headerLocator;
     }
 
@@ -205,7 +209,7 @@ public function getHeaderLocator(): Header\HeaderLocatorInterface
      * @todo Return self when we update to 7.4 or later as minimum PHP version.
      * @return $this
      */
-    public function setHeaderLocator(Header\HeaderLocatorInterface $headerLocator)
+    public function setHeaderLocator(HeaderLocatorInterface $headerLocator)
     {
         $this->headerLocator = $headerLocator;
         return $this;
diff --git a/src/Message.php b/src/Message.php
index eda49a69..f0e74840 100644
--- a/src/Message.php
+++ b/src/Message.php
@@ -305,11 +305,9 @@ public function getReplyTo()
     /**
      * setSender
      *
-     * @param mixed $emailOrAddress
-     * @param mixed $name
      * @return Message
      */
-    public function setSender($emailOrAddress, $name = null)
+    public function setSender(mixed $emailOrAddress, mixed $name = null)
     {
         /** @var Sender $header */
         $header = $this->getHeaderByName('sender', Sender::class);
diff --git a/src/Protocol/AbstractProtocol.php b/src/Protocol/AbstractProtocol.php
index d4dabd5c..9dfe67c3 100644
--- a/src/Protocol/AbstractProtocol.php
+++ b/src/Protocol/AbstractProtocol.php
@@ -18,10 +18,10 @@
 use function restore_error_handler;
 use function set_error_handler;
 use function sprintf;
+use function str_starts_with;
 use function stream_get_meta_data;
 use function stream_set_timeout;
 use function stream_socket_client;
-use function strpos;
 
 use const E_WARNING;
 use const PREG_SPLIT_DELIM_CAPTURE;
@@ -58,13 +58,6 @@ abstract class AbstractProtocol
      */
     protected $host;
 
-    /**
-     * Port number of connection
-     *
-     * @var int
-     */
-    protected $port;
-
     /**
      * Instance of Laminas\Validator\ValidatorChain to check hostnames
      *
@@ -95,17 +88,15 @@ abstract class AbstractProtocol
 
     /**
      * Log of mail requests and server responses for a session
-     *
-     * @var array
      */
-    private $log = [];
+    private array $log = [];
 
     /**
      * @param  string  $host OPTIONAL Hostname of remote connection (default: 127.0.0.1)
      * @param  int $port OPTIONAL Port number (default: null)
      * @throws Exception\RuntimeException
      */
-    public function __construct($host = '127.0.0.1', $port = null)
+    public function __construct($host = '127.0.0.1', protected $port = null)
     {
         $this->validHost = new Validator\ValidatorChain();
         $this->validHost->attach(new Validator\Hostname(Validator\Hostname::ALLOW_ALL));
@@ -115,7 +106,6 @@ public function __construct($host = '127.0.0.1', $port = null)
         }
 
         $this->host = $host;
-        $this->port = $port;
     }
 
     /**
@@ -227,7 +217,7 @@ protected function _connect($remote)
 
         // open connection
         set_error_handler(
-            function ($error, $message = '') {
+            static function ($error, $message = '') {
                 throw new Exception\RuntimeException(sprintf('Could not open socket: %s', $message), $error);
             },
             E_WARNING
@@ -359,7 +349,7 @@ protected function _expect($code, $timeout = null)
             }
 
         // The '-' message prefix indicates an information string instead of a response string.
-        } while (strpos($more, '-') === 0);
+        } while (str_starts_with($more, '-'));
 
         if ($errMsg !== '') {
             throw new Exception\RuntimeException($errMsg);
diff --git a/src/Protocol/Imap.php b/src/Protocol/Imap.php
index 8f75911e..d8b20724 100644
--- a/src/Protocol/Imap.php
+++ b/src/Protocol/Imap.php
@@ -24,7 +24,9 @@
 use function next;
 use function preg_match;
 use function rtrim;
+use function str_contains;
 use function str_replace;
+use function str_starts_with;
 use function stream_socket_enable_crypto;
 use function strlen;
 use function strpos;
@@ -154,7 +156,7 @@ protected function nextLine()
     protected function assumedNextLine($start)
     {
         $line = $this->nextLine();
-        return strpos($line, $start) === 0;
+        return str_starts_with($line, $start);
     }
 
     /**
@@ -318,7 +320,7 @@ public function readResponse($tag, $dontParse = false)
 
         // last line has response code
         if ($tokens[0] == 'OK') {
-            return $lines ? $lines : true;
+            return $lines ?: true;
         } elseif ($tokens[0] == 'NO') {
             return false;
         }
@@ -385,7 +387,7 @@ public function requestAndResponse($command, $tokens = [], $dontParse = false)
     public function escapeString($string)
     {
         if (func_num_args() < 2) {
-            if (strpos($string, "\n") !== false) {
+            if (str_contains($string, "\n")) {
                 return ['{' . strlen($string) . '}', $string];
             }
 
@@ -441,7 +443,7 @@ public function logout()
         if ($this->socket) {
             try {
                 $result = $this->requestAndResponse('LOGOUT', [], true);
-            } catch (Exception\ExceptionInterface $e) {
+            } catch (Exception\ExceptionInterface) {
                 // ignoring exception
             }
             fclose($this->socket);
diff --git a/src/Protocol/Pop3.php b/src/Protocol/Pop3.php
index 9ddbfa4f..a097823c 100644
--- a/src/Protocol/Pop3.php
+++ b/src/Protocol/Pop3.php
@@ -209,7 +209,7 @@ public function logout()
         if ($this->socket) {
             try {
                 $this->request('QUIT');
-            } catch (Exception\ExceptionInterface $e) {
+            } catch (Exception\ExceptionInterface) {
                 // ignore error - we're closing the socket anyway
             }
 
@@ -242,7 +242,7 @@ public function login($user, $password, $tryApop = true)
             try {
                 $this->request("APOP $user " . md5($this->timestamp . $password));
                 return;
-            } catch (Exception\ExceptionInterface $e) {
+            } catch (Exception\ExceptionInterface) {
                 // ignore
             }
         }
diff --git a/src/Protocol/Smtp.php b/src/Protocol/Smtp.php
index b8b117e0..f35ca72c 100644
--- a/src/Protocol/Smtp.php
+++ b/src/Protocol/Smtp.php
@@ -326,7 +326,7 @@ protected function ehlo($host)
         try {
             $this->_send('EHLO ' . $host);
             $this->_expect(250, 300); // Timeout set for 5 minutes as per RFC 2821 4.5.3.2
-        } catch (Exception\ExceptionInterface $e) {
+        } catch (Exception\ExceptionInterface) {
             $this->_send('HELO ' . $host);
             $this->_expect(250, 300); // Timeout set for 5 minutes as per RFC 2821 4.5.3.2
         }
diff --git a/src/Protocol/SmtpPluginManagerFactory.php b/src/Protocol/SmtpPluginManagerFactory.php
index 956855f9..f63b8509 100644
--- a/src/Protocol/SmtpPluginManagerFactory.php
+++ b/src/Protocol/SmtpPluginManagerFactory.php
@@ -47,7 +47,6 @@ public function createService(ServiceLocatorInterface $container, $name = null,
     /**
      * laminas-servicemanager v2 support for invocation options.
      *
-     * @param array $options
      * @psalm-param ServiceManagerConfiguration $options
      * @return void
      */
diff --git a/src/Storage/AbstractStorage.php b/src/Storage/AbstractStorage.php
index 94d21c81..3c8e19ea 100644
--- a/src/Storage/AbstractStorage.php
+++ b/src/Storage/AbstractStorage.php
@@ -8,7 +8,7 @@
 use ReturnTypeWillChange;
 use SeekableIterator;
 
-use function strpos;
+use function str_starts_with;
 use function strtolower;
 use function substr;
 
@@ -67,7 +67,7 @@ abstract class AbstractStorage implements
      */
     public function __get($var)
     {
-        if (strpos($var, 'has') === 0) {
+        if (str_starts_with($var, 'has')) {
             $var = strtolower(substr($var, 3));
             return $this->has[$var] ?? null;
         }
@@ -211,7 +211,7 @@ public function offsetExists($id)
             if ($this->getMessage($id)) {
                 return true;
             }
-        } catch (Exception\ExceptionInterface $e) {
+        } catch (Exception\ExceptionInterface) {
         }
 
         return false;
@@ -232,12 +232,10 @@ public function offsetGet($id)
     /**
      * ArrayAccess::offsetSet()
      *
-     * @param mixed $id
-     * @param mixed $value
      * @throws Exception\RuntimeException
      */
     #[ReturnTypeWillChange]
-    public function offsetSet($id, $value)
+    public function offsetSet(mixed $id, mixed $value)
     {
         throw new Exception\RuntimeException('cannot write mail messages via array access');
     }
diff --git a/src/Storage/Folder.php b/src/Storage/Folder.php
index 52053e46..ab89a153 100644
--- a/src/Storage/Folder.php
+++ b/src/Storage/Folder.php
@@ -4,28 +4,15 @@
 
 use RecursiveIterator;
 use ReturnTypeWillChange;
+use Stringable;
 
 use function current;
 use function key;
 use function next;
 use function reset;
 
-class Folder implements RecursiveIterator
+class Folder implements RecursiveIterator, Stringable
 {
-    /**
-     * subfolders of folder array(localName => \Laminas\Mail\Storage\Folder folder)
-     *
-     * @var array<string, self>
-     */
-    protected $folders;
-
-    /**
-     * local name (name of folder in parent folder)
-     *
-     * @var string
-     */
-    protected $localName;
-
     /**
      * global name (absolute name of folder)
      *
@@ -33,28 +20,23 @@ class Folder implements RecursiveIterator
      */
     protected $globalName;
 
-    /**
-     * folder is selectable if folder is able to hold messages, otherwise it is a parent folder
-     *
-     * @var bool
-     */
-    protected $selectable = true;
-
     /**
      * create a new mail folder instance
      *
-     * @param string $localName  name of folder in current subdirectory
+     * @param string $localName  local name (name of folder in parent folder)
      * @param string $globalName absolute name of folder
      * @param bool $selectable if true folder holds messages, if false it's
      *     just a parent for subfolders (Default: true)
-     * @param array<string, Folder> $folders init with given instances of Folder as subfolders
-     */
-    public function __construct($localName, $globalName = '', $selectable = true, array $folders = [])
-    {
-        $this->localName  = $localName;
+     * @param array<string, Folder> $folders subfolders of
+     *     folder array(localName => \Laminas\Mail\Storage\Folder folder)
+     */
+    public function __construct(
+        protected $localName,
+        $globalName = '',
+        protected $selectable = true,
+        protected array $folders = []
+    ) {
         $this->globalName = $globalName ?: $localName;
-        $this->selectable = $selectable;
-        $this->folders    = $folders;
     }
 
     /**
@@ -173,7 +155,7 @@ public function __unset($name)
      *
      * @return string global name of folder
      */
-    public function __toString()
+    public function __toString(): string
     {
         return (string) $this->getGlobalName();
     }
diff --git a/src/Storage/Folder/Maildir.php b/src/Storage/Folder/Maildir.php
index 199e8045..e31fcaf9 100644
--- a/src/Storage/Folder/Maildir.php
+++ b/src/Storage/Folder/Maildir.php
@@ -18,8 +18,9 @@
 use function readdir;
 use function rtrim;
 use function sort;
+use function str_contains;
+use function str_starts_with;
 use function strlen;
-use function strpos;
 use function substr;
 use function trim;
 
@@ -136,9 +137,9 @@ protected function buildFolderTree()
 
         foreach ($dirs as $dir) {
             do {
-                if (strpos($dir, $parent) === 0) {
-                    $local = substr($dir, strlen($parent));
-                    if (strpos($local, $this->delim) !== false) {
+                if (str_starts_with($dir, $parent)) {
+                    $local = substr($dir, strlen((string) $parent));
+                    if (str_contains($local, $this->delim)) {
                         throw new Exception\RuntimeException('error while reading maildir');
                     }
                     array_push($stack, $parent);
@@ -173,14 +174,14 @@ public function getFolders($rootFolder = null)
         }
 
         // rootdir is same as INBOX in maildir
-        if (strpos($rootFolder, 'INBOX' . $this->delim) === 0) {
+        if (str_starts_with($rootFolder, 'INBOX' . $this->delim)) {
             $rootFolder = substr($rootFolder, 6);
         }
         $currentFolder = $this->rootFolder;
         $subname       = trim($rootFolder, $this->delim);
 
         while ($currentFolder) {
-            if (false !== strpos($subname, $this->delim)) {
+            if (str_contains($subname, $this->delim)) {
                 [$entry, $subname] = explode($this->delim, $subname, 2);
             } else {
                 $entry   = $subname;
diff --git a/src/Storage/Folder/Mbox.php b/src/Storage/Folder/Mbox.php
index 991a02e1..3b6f540a 100644
--- a/src/Storage/Folder/Mbox.php
+++ b/src/Storage/Folder/Mbox.php
@@ -16,7 +16,7 @@
 use function readdir;
 use function rtrim;
 use function sprintf;
-use function strpos;
+use function str_contains;
 use function trim;
 
 use const DIRECTORY_SEPARATOR;
@@ -149,7 +149,7 @@ public function getFolders($rootFolder = null)
         $currentFolder = $this->rootFolder;
         $subname       = trim($rootFolder, DIRECTORY_SEPARATOR);
         while ($currentFolder) {
-            if (false !== strpos($subname, DIRECTORY_SEPARATOR)) {
+            if (str_contains($subname, DIRECTORY_SEPARATOR)) {
                 [$entry, $subname] = explode(DIRECTORY_SEPARATOR, $subname, 2);
             } else {
                 $entry   = $subname;
diff --git a/src/Storage/Imap.php b/src/Storage/Imap.php
index 04a1e329..25dc1b13 100644
--- a/src/Storage/Imap.php
+++ b/src/Storage/Imap.php
@@ -12,7 +12,7 @@
 use function in_array;
 use function is_string;
 use function ksort;
-use function strpos;
+use function str_starts_with;
 use function strrpos;
 use function substr;
 
@@ -357,8 +357,8 @@ public function getFolders($rootFolder = null)
 
         foreach ($folders as $globalName => $data) {
             do {
-                if (! $parent || strpos($globalName, $parent) === 0) {
-                    $pos = strrpos($globalName, $data['delim']);
+                if (! $parent || str_starts_with($globalName, ! is_string($parent) ? (string) $parent : $parent)) {
+                    $pos = strrpos($globalName, (string) $data['delim']);
                     if ($pos === false) {
                         $localName = $globalName;
                     } else {
diff --git a/src/Storage/Maildir.php b/src/Storage/Maildir.php
index 19f68e93..4936d699 100644
--- a/src/Storage/Maildir.php
+++ b/src/Storage/Maildir.php
@@ -25,10 +25,10 @@
 use function opendir;
 use function readdir;
 use function sprintf;
+use function str_contains;
 use function strcmp;
 use function stream_get_contents;
 use function strlen;
-use function strpos;
 use function substr;
 use function trim;
 use function usort;
@@ -332,14 +332,14 @@ protected function getMaildirFiles($dh, $dirname, $defaultFlags = [])
                 continue;
             }
 
-            if (false !== strpos($entry, ':')) {
+            if (str_contains($entry, ':')) {
                 [$uniq, $info] = explode(':', $entry, 2);
             } else {
                 $uniq = $entry;
                 $info = '';
             }
 
-            if (false !== strpos($uniq, ',')) {
+            if (str_contains($uniq, ',')) {
                 [, $size] = explode(',', $uniq, 2);
             } else {
                 $size = '';
@@ -353,7 +353,7 @@ protected function getMaildirFiles($dh, $dirname, $defaultFlags = [])
                 $size = null;
             }
 
-            if (false !== strpos($info, ',')) {
+            if (str_contains($info, ',')) {
                 [$version, $flags] = explode(',', $info, 2);
             } else {
                 $version = $info;
@@ -383,9 +383,7 @@ protected function getMaildirFiles($dh, $dirname, $defaultFlags = [])
             $this->files[] = $data;
         }
 
-        usort($this->files, function ($a, $b): int {
-            return strcmp($a['filename'], $b['filename']);
-        });
+        usort($this->files, static fn($a, $b): int => strcmp($a['filename'], $b['filename']));
     }
 
     /**
diff --git a/src/Storage/Mbox.php b/src/Storage/Mbox.php
index d0f219cf..b4db7bd1 100644
--- a/src/Storage/Mbox.php
+++ b/src/Storage/Mbox.php
@@ -19,9 +19,9 @@
 use function is_resource;
 use function is_subclass_of;
 use function range;
+use function str_starts_with;
 use function stream_get_contents;
 use function strlen;
-use function strpos;
 use function strtolower;
 use function trim;
 
@@ -259,7 +259,7 @@ protected function isMboxFile($file, $fileIsString = true)
         $result = false;
 
         $line = fgets($file) ?: '';
-        if (strpos($line, 'From ') === 0) {
+        if (str_starts_with($line, 'From ')) {
             $result = true;
         }
 
@@ -307,7 +307,7 @@ protected function openMboxFile($filename)
 
         $messagePos = ['start' => ftell($this->fh), 'separator' => 0, 'end' => 0];
         while (($line = fgets($this->fh)) !== false) {
-            if (strpos($line, 'From ') === 0) {
+            if (str_starts_with($line, 'From ')) {
                 $messagePos['end'] = ftell($this->fh) - strlen($line) - 2; // + newline
                 if (! $messagePos['separator']) {
                     $messagePos['separator'] = $messagePos['end'];
diff --git a/src/Storage/ParamsNormalizer.php b/src/Storage/ParamsNormalizer.php
index c9f57b80..a6ad81c5 100644
--- a/src/Storage/ParamsNormalizer.php
+++ b/src/Storage/ParamsNormalizer.php
@@ -18,10 +18,9 @@
 final class ParamsNormalizer
 {
     /**
-     * @param mixed $params
      * @return array<string, mixed>
      */
-    public static function normalizeParams($params): array
+    public static function normalizeParams(mixed $params): array
     {
         if ($params instanceof Traversable) {
             $params = iterator_to_array($params);
diff --git a/src/Storage/Part.php b/src/Storage/Part.php
index 0abb76d8..26b761c0 100644
--- a/src/Storage/Part.php
+++ b/src/Storage/Part.php
@@ -9,6 +9,7 @@
 use Laminas\Mime\Exception\RuntimeException;
 use RecursiveIterator;
 use ReturnTypeWillChange;
+use Stringable;
 
 use function array_map;
 use function count;
@@ -22,7 +23,7 @@
 use function strtolower;
 use function trim;
 
-class Part implements RecursiveIterator, Part\PartInterface
+class Part implements RecursiveIterator, Part\PartInterface, Stringable
 {
     /**
      * Headers of the part
@@ -109,7 +110,7 @@ public function __construct(array $params)
             $this->messageNum = $params['id'];
         }
 
-        $params['strict'] = $params['strict'] ?? false;
+        $params['strict'] ??= false;
 
         if (isset($params['raw'])) {
             Mime\Decode::splitMessage(
@@ -146,7 +147,7 @@ public function isMultipart()
     {
         try {
             return stripos($this->contentType, 'multipart/') === 0;
-        } catch (Exception\ExceptionInterface $e) {
+        } catch (Exception\ExceptionInterface) {
             return false;
         }
     }
@@ -332,9 +333,8 @@ public function getHeader($name, $format = null)
                 } else {
                     $return = trim(implode(
                         Mime\Mime::LINEEND,
-                        array_map(static function ($header): string {
-                                return $header->getFieldValue(HeaderInterface::FORMAT_RAW);
-                        }, iterator_to_array($header))
+                        array_map(static fn($header): string
+                            => $header->getFieldValue(HeaderInterface::FORMAT_RAW), iterator_to_array($header))
                     ), Mime\Mime::LINEEND);
                 }
                 break;
@@ -411,7 +411,7 @@ public function __isset($name)
      *
      * @return string content
      */
-    public function __toString()
+    public function __toString(): string
     {
         return $this->getContent();
     }
diff --git a/src/Storage/Pop3.php b/src/Storage/Pop3.php
index 4a9e5a6f..633f3161 100644
--- a/src/Storage/Pop3.php
+++ b/src/Storage/Pop3.php
@@ -49,7 +49,7 @@ public function countMessages()
      */
     public function getSize($id = 0)
     {
-        $id = $id ? $id : null;
+        $id = $id ?: null;
         return $this->protocol->getList($id);
     }
 
@@ -276,7 +276,7 @@ public function __get($var)
                 // need to make a real call, because not all server are honest in their capas
                 try {
                     $this->protocol->top(1, 0, false);
-                } catch (MailException\ExceptionInterface $e) {
+                } catch (MailException\ExceptionInterface) {
                     // ignoring error
                 }
             }
@@ -288,7 +288,7 @@ public function __get($var)
             $id = null;
             try {
                 $id = $this->protocol->uniqueid(1);
-            } catch (MailException\ExceptionInterface $e) {
+            } catch (MailException\ExceptionInterface) {
                 // ignoring error
             }
             $this->has['uniqueid'] = (bool) $id;
diff --git a/src/Storage/Writable/Maildir.php b/src/Storage/Writable/Maildir.php
index bdab378a..fe8a162a 100644
--- a/src/Storage/Writable/Maildir.php
+++ b/src/Storage/Writable/Maildir.php
@@ -47,6 +47,8 @@
 use function rmdir;
 use function rtrim;
 use function sleep;
+use function str_contains;
+use function str_starts_with;
 use function stream_copy_to_stream;
 use function strlen;
 use function strpos;
@@ -168,18 +170,18 @@ public function createFolder($name, $parentFolder = null)
         $exists = null;
         try {
             $exists = $this->getFolders($folder);
-        } catch (MailException\ExceptionInterface $e) {
+        } catch (MailException\ExceptionInterface) {
             // ok
         }
         if ($exists) {
             throw new StorageException\RuntimeException('folder already exists');
         }
 
-        if (strpos($folder, $this->delim . $this->delim) !== false) {
+        if (str_contains($folder, $this->delim . $this->delim)) {
             throw new StorageException\RuntimeException('invalid name - folder parts may not be empty');
         }
 
-        if (strpos($folder, 'INBOX' . $this->delim) === 0) {
+        if (str_starts_with($folder, 'INBOX' . $this->delim)) {
             $folder = substr($folder, 6);
         }
 
@@ -187,7 +189,7 @@ public function createFolder($name, $parentFolder = null)
 
         // check if we got tricked and would create a dir outside of the rootdir or not as direct child
         if (
-            strpos($folder, DIRECTORY_SEPARATOR) !== false || strpos($folder, '/') !== false
+            str_contains($folder, DIRECTORY_SEPARATOR) || str_contains($folder, '/')
             || dirname($fulldir) . DIRECTORY_SEPARATOR != $this->rootdir
         ) {
             throw new StorageException\RuntimeException('invalid name - no directory separator allowed in folder name');
@@ -200,7 +202,7 @@ public function createFolder($name, $parentFolder = null)
             $parent = substr($folder, 0, strrpos($folder, $this->delim));
             try {
                 $this->getFolders($parent);
-            } catch (MailException\ExceptionInterface $e) {
+            } catch (MailException\ExceptionInterface) {
                 // does not - create parent folder
                 $this->createFolder($parent);
             }
@@ -245,7 +247,7 @@ public function removeFolder($name)
         }
 
         $name = trim($name, $this->delim);
-        if (strpos($name, 'INBOX' . $this->delim) === 0) {
+        if (str_starts_with($name, 'INBOX' . $this->delim)) {
             $name = substr($name, 6);
         }
 
@@ -316,16 +318,16 @@ public function renameFolder($oldName, $newName)
         }
 
         $oldName = trim($oldName, $this->delim);
-        if (strpos($oldName, 'INBOX' . $this->delim) === 0) {
+        if (str_starts_with($oldName, 'INBOX' . $this->delim)) {
             $oldName = substr($oldName, 6);
         }
 
         $newName = trim($newName, $this->delim);
-        if (strpos($newName, 'INBOX' . $this->delim) === 0) {
+        if (str_starts_with($newName, 'INBOX' . $this->delim)) {
             $newName = substr($newName, 6);
         }
 
-        if (strpos($newName, $oldName . $this->delim) === 0) {
+        if (str_starts_with($newName, $oldName . $this->delim)) {
             throw new StorageException\RuntimeException('new folder cannot be a child of old folder');
         }
 
diff --git a/src/Transport/FileOptions.php b/src/Transport/FileOptions.php
index fd1c0289..6f21cb87 100644
--- a/src/Transport/FileOptions.php
+++ b/src/Transport/FileOptions.php
@@ -87,9 +87,7 @@ public function setCallback($callback)
     public function getCallback()
     {
         if (null === $this->callback) {
-            $this->setCallback(function () {
-                return 'LaminasMail_' . time() . '_' . mt_rand() . '.eml';
-            });
+            $this->setCallback(static fn() => 'LaminasMail_' . time() . '_' . mt_rand() . '.eml');
         }
         return $this->callback;
     }
diff --git a/src/Transport/Sendmail.php b/src/Transport/Sendmail.php
index 76fc6763..aae76f49 100644
--- a/src/Transport/Sendmail.php
+++ b/src/Transport/Sendmail.php
@@ -22,8 +22,8 @@
 use function restore_error_handler;
 use function set_error_handler;
 use function sprintf;
+use function str_contains;
 use function str_replace;
-use function strpos;
 use function strtoupper;
 use function substr;
 use function trim;
@@ -240,7 +240,7 @@ protected function prepareHeaders(Mail\Message $message)
         $from = $headers->get('From');
         if ($from) {
             foreach ($from->getAddressList() as $address) {
-                if (strpos($address->getEmail(), '\\"') !== false) {
+                if (str_contains($address->getEmail(), '\\"')) {
                     throw new RuntimeException('Potential code injection in From header');
                 }
             }
diff --git a/src/Transport/Smtp.php b/src/Transport/Smtp.php
index 525b3c24..2188b37f 100644
--- a/src/Transport/Smtp.php
+++ b/src/Transport/Smtp.php
@@ -144,7 +144,6 @@ public function getAutoDisconnect()
      * Return an SMTP connection
      *
      * @param  string $name
-     * @param  array|null $options
      * @return Protocol\Smtp
      */
     public function plugin($name, ?array $options = null)
@@ -164,7 +163,7 @@ public function __destruct()
 
         try {
             $connection->quit();
-        } catch (ProtocolException\ExceptionInterface $e) {
+        } catch (ProtocolException\ExceptionInterface) {
             // ignore
         }
 
diff --git a/src/Transport/SmtpOptions.php b/src/Transport/SmtpOptions.php
index 71690ebc..59984706 100644
--- a/src/Transport/SmtpOptions.php
+++ b/src/Transport/SmtpOptions.php
@@ -116,7 +116,6 @@ public function getConnectionConfig()
     /**
      * Set connection configuration array
      *
-     * @param  array $connectionConfig
      * @return SmtpOptions
      */
     public function setConnectionConfig(array $connectionConfig)
diff --git a/test/AddressListTest.php b/test/AddressListTest.php
index f3910278..c57f745a 100644
--- a/test/AddressListTest.php
+++ b/test/AddressListTest.php
@@ -18,8 +18,7 @@
  */
 class AddressListTest extends TestCase
 {
-    /** @var AddressList */
-    private $list;
+    private AddressList $list;
 
     public function setUp(): void
     {
@@ -162,7 +161,7 @@ public function testSemicolonSeparator(): void
         // length'; hence the try/catch block, to allow finding the root cause.
         try {
             $to = Header\To::fromString('To:' . $header);
-        } catch (InvalidArgumentException $e) {
+        } catch (InvalidArgumentException) {
             $this->fail('Header\To::fromString should not throw');
         }
         $addressList = $to->getAddressList();
@@ -220,7 +219,7 @@ public function testMixedQuotesInName(): void
         // hence the try/catch block, to allow finding the root cause.
         try {
             $to = Header\To::fromString('To:' . $header);
-        } catch (InvalidArgumentException $e) {
+        } catch (InvalidArgumentException) {
             $this->fail('Header\To::fromString should not throw');
         }
 
diff --git a/test/Header/GenericHeaderTest.php b/test/Header/GenericHeaderTest.php
index 9d2964a9..6d46977b 100644
--- a/test/Header/GenericHeaderTest.php
+++ b/test/Header/GenericHeaderTest.php
@@ -55,9 +55,8 @@ public function fieldNames(): array
     /**
      * @dataProvider fieldNames
      * @group ZF2015-04
-     * @param mixed $fieldName
      */
-    public function testConstructorRaisesExceptionOnInvalidFieldName($fieldName): void
+    public function testConstructorRaisesExceptionOnInvalidFieldName(mixed $fieldName): void
     {
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('name');
@@ -68,9 +67,8 @@ public function testConstructorRaisesExceptionOnInvalidFieldName($fieldName): vo
     /**
      * @dataProvider fieldNames
      * @group ZF2015-04
-     * @param mixed $fieldName
      */
-    public function testSetFieldNameRaisesExceptionOnInvalidFieldName($fieldName): void
+    public function testSetFieldNameRaisesExceptionOnInvalidFieldName(mixed $fieldName): void
     {
         $header = new GenericHeader('Subject');
         $this->expectException(InvalidArgumentException::class);
diff --git a/test/Header/HeaderLocatorTest.php b/test/Header/HeaderLocatorTest.php
index cf4ec08e..da8f5749 100644
--- a/test/Header/HeaderLocatorTest.php
+++ b/test/Header/HeaderLocatorTest.php
@@ -3,12 +3,12 @@
 namespace LaminasTest\Mail\Header;
 
 use Laminas\Mail\Header;
+use Laminas\Mail\Header\HeaderLocator;
 use PHPUnit\Framework\TestCase;
 
 class HeaderLocatorTest extends TestCase
 {
-    /** @var Header\HeaderLocator */
-    private $headerLocator;
+    private HeaderLocator $headerLocator;
 
     public function setUp(): void
     {
diff --git a/test/Header/SenderTest.php b/test/Header/SenderTest.php
index eb43c075..20a7001b 100644
--- a/test/Header/SenderTest.php
+++ b/test/Header/SenderTest.php
@@ -142,16 +142,15 @@ public function validSenderDataProvider(): array
 
     public function validSenderHeaderDataProvider(): array
     {
-        return array_merge(array_map(function ($parameters) {
-            return array_slice($parameters, 2);
-        }, $this->validSenderDataProvider()), [
+        return array_merge(array_map(static fn($parameters)
+            => array_slice($parameters, 2), $this->validSenderDataProvider()), [
             // Per RFC 2822, 3.4 and 3.6.2, "Sender: foo@bar" is valid.
-            'Unbracketed email' => [
-                '<foo@bar>',
-                'foo@bar',
-                'ASCII',
-            ],
-        ]);
+                'Unbracketed email' => [
+                    '<foo@bar>',
+                    'foo@bar',
+                    'ASCII',
+                ],
+            ]);
     }
 
     public function invalidSenderDataProvider(): array
diff --git a/test/HeadersTest.php b/test/HeadersTest.php
index d0762b0d..d2994cfb 100644
--- a/test/HeadersTest.php
+++ b/test/HeadersTest.php
@@ -46,7 +46,7 @@ public function tearDown(): void
     public function setDeprecationErrorHandler(): void
     {
         $this->originalErrorHandler = set_error_handler(
-            function (int $errno, string $errstr, string $errfile, int $errline): void {
+            static function (int $errno, string $errstr, string $errfile, int $errline): void {
                 /** @psalm-suppress InternalMethod */
                 throw new Deprecated($errstr, $errno, $errfile, $errline);
             },
diff --git a/test/MessageFactoryTest.php b/test/MessageFactoryTest.php
index 2bb74ee7..11da700c 100644
--- a/test/MessageFactoryTest.php
+++ b/test/MessageFactoryTest.php
@@ -115,9 +115,8 @@ public function invalidMessageOptions(): array
 
     /**
      * @dataProvider invalidMessageOptions
-     * @param mixed $options
      */
-    public function testExceptionForOptionsNotArrayOrTraversable($options): void
+    public function testExceptionForOptionsNotArrayOrTraversable(mixed $options): void
     {
         $this->expectException(Exception\InvalidArgumentException::class);
         MessageFactory::getInstance($options);
diff --git a/test/MessageTest.php b/test/MessageTest.php
index 272a19fe..f81ecdd7 100644
--- a/test/MessageTest.php
+++ b/test/MessageTest.php
@@ -539,9 +539,8 @@ public static function invalidBodyValues(): array
 
     /**
      * @dataProvider invalidBodyValues
-     * @param mixed $body
      */
-    public function testSettingNonScalarNonMimeNonStringSerializableValueForBodyRaisesException($body): void
+    public function testSettingNonScalarNonMimeNonStringSerializableValueForBodyRaisesException(mixed $body): void
     {
         $this->expectException(Exception\InvalidArgumentException::class);
         $this->message->setBody($body);
diff --git a/test/Protocol/AbstractProtocolTest.php b/test/Protocol/AbstractProtocolTest.php
index aca421b6..5adc4b23 100644
--- a/test/Protocol/AbstractProtocolTest.php
+++ b/test/Protocol/AbstractProtocolTest.php
@@ -12,7 +12,7 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Process\Process;
 
-use function strpos;
+use function str_contains;
 
 use const PHP_BINARY;
 
@@ -22,8 +22,7 @@
  */
 final class AbstractProtocolTest extends TestCase
 {
-    /** @var Process */
-    private $process;
+    private Process $process;
 
     protected function setUp(): void
     {
@@ -35,9 +34,7 @@ protected function setUp(): void
             __DIR__ . '/HttpStatusService',
         ]);
         $this->process->start();
-        $this->process->waitUntil(static function (string $type, string $output): bool {
-            return false !== strpos($output, 'started');
-        });
+        $this->process->waitUntil(static fn(string $type, string $output): bool => str_contains($output, 'started'));
     }
 
     protected function tearDown(): void
diff --git a/test/Storage/MaildirFolderTest.php b/test/Storage/MaildirFolderTest.php
index 680649e8..4d37da40 100644
--- a/test/Storage/MaildirFolderTest.php
+++ b/test/Storage/MaildirFolderTest.php
@@ -79,7 +79,7 @@ public function setUp(): void
                 $phar->extractTo($originalMaildir);
                 // This empty directory is in the tar, but not unpacked by PharData
                 mkdir($originalMaildir . '.subfolder/cur');
-            } catch (\Exception $e) {
+            } catch (\Exception) {
                 // intentionally empty catch block
             }
         }
@@ -354,7 +354,7 @@ public function testNotReadableFolder(): void
         $check = false;
         try {
             $mail = new Folder\Maildir($this->params);
-        } catch (\Exception $e) {
+        } catch (\Exception) {
             $check = true;
             // test ok
         }
diff --git a/test/Storage/MaildirMessageOldTest.php b/test/Storage/MaildirMessageOldTest.php
index 71445f50..3b0bb00f 100644
--- a/test/Storage/MaildirMessageOldTest.php
+++ b/test/Storage/MaildirMessageOldTest.php
@@ -67,7 +67,7 @@ public function setUp(): void
             try {
                 $phar = new PharData($originalMaildir . 'maildir.tar');
                 $phar->extractTo($originalMaildir);
-            } catch (Exception $e) {
+            } catch (Exception) {
                 // intentionally empty catch block
             }
         }
diff --git a/test/Storage/MaildirTest.php b/test/Storage/MaildirTest.php
index e3b27941..6cc92053 100644
--- a/test/Storage/MaildirTest.php
+++ b/test/Storage/MaildirTest.php
@@ -74,7 +74,7 @@ public function setUp(): void
             try {
                 $phar = new PharData($originalMaildir . 'maildir.tar');
                 $phar->extractTo($originalMaildir);
-            } catch (\Exception $e) {
+            } catch (\Exception) {
                 // intentionally empty catch block
             }
         }
diff --git a/test/Storage/MaildirWritableTest.php b/test/Storage/MaildirWritableTest.php
index fa0bc156..6fce264d 100644
--- a/test/Storage/MaildirWritableTest.php
+++ b/test/Storage/MaildirWritableTest.php
@@ -77,7 +77,7 @@ public function setUp(): void
             try {
                 $phar = new PharData($originalMaildir . 'maildir.tar');
                 $phar->extractTo($originalMaildir);
-            } catch (\Exception $e) {
+            } catch (\Exception) {
                 // intentionally empty catch block
             }
         }
@@ -575,7 +575,7 @@ public function testInit(): void
         try {
             $mail = new Writable\Maildir($this->params);
             $this->fail('empty maildir should not be accepted');
-        } catch (\Exception $e) {
+        } catch (\Exception) {
         }
 
         Writable\Maildir::initMaildir($this->params['dirname']);
@@ -592,7 +592,7 @@ public function testCreate(): void
         try {
             $mail = new Writable\Maildir($this->params);
             $this->fail('empty maildir should not be accepted');
-        } catch (\Exception $e) {
+        } catch (\Exception) {
         }
 
         $this->params['create'] = true;
diff --git a/test/Storage/MboxFolderTest.php b/test/Storage/MboxFolderTest.php
index 0acbdb00..eab4359b 100644
--- a/test/Storage/MboxFolderTest.php
+++ b/test/Storage/MboxFolderTest.php
@@ -329,7 +329,7 @@ public function testNotReadableFolder(): void
         $check = false;
         try {
             $mail = new Folder\Mbox($this->params);
-        } catch (\Exception $e) {
+        } catch (\Exception) {
             $check = true;
             // test ok
         }
diff --git a/test/Storage/MboxTest.php b/test/Storage/MboxTest.php
index 8876e42c..52f5a667 100644
--- a/test/Storage/MboxTest.php
+++ b/test/Storage/MboxTest.php
@@ -303,7 +303,7 @@ public function testSleepWakeRemoved(): void
         $check = false;
         try {
             $mail = unserialize($serialzed);
-        } catch (\Exception $e) {
+        } catch (\Exception) {
             $check = true;
             // test ok
         }
diff --git a/test/Storage/MessageTest.php b/test/Storage/MessageTest.php
index 2ba8e16a..cfb07989 100644
--- a/test/Storage/MessageTest.php
+++ b/test/Storage/MessageTest.php
@@ -317,7 +317,7 @@ public function testEmptyBody(): void
         $part    = null;
         try {
             $part = $message->getPart(1);
-        } catch (Exception\RuntimeException $e) {
+        } catch (Exception\RuntimeException) {
             // ok
         }
         if ($part) {
diff --git a/test/Storage/ParamsNormalizerTest.php b/test/Storage/ParamsNormalizerTest.php
index 0aec4cac..76d1b8e1 100644
--- a/test/Storage/ParamsNormalizerTest.php
+++ b/test/Storage/ParamsNormalizerTest.php
@@ -22,9 +22,8 @@ public function invalidParams(): iterable
 
     /**
      * @dataProvider invalidParams
-     * @param mixed $params
      */
-    public function testRaisesErrorOnInvalidParamsTypes($params): void
+    public function testRaisesErrorOnInvalidParamsTypes(mixed $params): void
     {
         $this->expectException(InvalidArgumentException::class);
         ParamsNormalizer::normalizeParams($params);
diff --git a/test/TestAsset/StringSerializableObject.php b/test/TestAsset/StringSerializableObject.php
index ecd7dfc3..69fd6ab5 100644
--- a/test/TestAsset/StringSerializableObject.php
+++ b/test/TestAsset/StringSerializableObject.php
@@ -2,20 +2,15 @@
 
 namespace LaminasTest\Mail\TestAsset;
 
-class StringSerializableObject
-{
-    /** @var string */
-    private $message;
+use Stringable;
 
-    public function __construct(string $message)
+class StringSerializableObject implements Stringable
+{
+    public function __construct(private string $message)
     {
-        $this->message = $message;
     }
 
-    /**
-     * @return string
-     */
-    public function __toString()
+    public function __toString(): string
     {
         return $this->message;
     }
diff --git a/test/Transport/FactoryTest.php b/test/Transport/FactoryTest.php
index 22a619ec..f23ca16f 100644
--- a/test/Transport/FactoryTest.php
+++ b/test/Transport/FactoryTest.php
@@ -27,9 +27,8 @@ class FactoryTest extends TestCase
 {
     /**
      * @dataProvider invalidSpecTypeProvider
-     * @param mixed $spec
      */
-    public function testInvalidSpecThrowsInvalidArgumentException($spec): void
+    public function testInvalidSpecThrowsInvalidArgumentException(mixed $spec): void
     {
         $this->expectException(Exception\InvalidArgumentException::class);
         Factory::create($spec);
@@ -56,7 +55,7 @@ public function testDefaultTypeIsSendmail(): void
      */
     public function testCanCreateClassUsingTypeKey(string $type): void
     {
-        set_error_handler(function ($code, $message): void {
+        set_error_handler(static function ($code, $message): void {
             // skip deprecation notices
         }, E_USER_DEPRECATED);
         $transport = Factory::create([
diff --git a/test/Transport/FileOptionsTest.php b/test/Transport/FileOptionsTest.php
index 1e03c4c1..212fb5ea 100644
--- a/test/Transport/FileOptionsTest.php
+++ b/test/Transport/FileOptionsTest.php
@@ -14,8 +14,7 @@
  */
 class FileOptionsTest extends TestCase
 {
-    /** @var FileOptions  */
-    private $options;
+    private FileOptions $options;
 
     public function setUp(): void
     {
@@ -47,7 +46,7 @@ public function testPathIsMutable(): void
     public function testCallbackIsMutable(): void
     {
         $original = $this->options->getCallback();
-        $new      = function ($transport): void {
+        $new      = static function ($transport): void {
         };
 
         $this->options->setCallback($new);
diff --git a/test/Transport/FileTest.php b/test/Transport/FileTest.php
index 3869d067..3c579e6d 100644
--- a/test/Transport/FileTest.php
+++ b/test/Transport/FileTest.php
@@ -8,7 +8,6 @@
 use PHPUnit\Framework\TestCase;
 
 use function file_get_contents;
-use function get_class;
 use function glob;
 use function is_dir;
 use function mkdir;
@@ -22,8 +21,7 @@
  */
 class FileTest extends TestCase
 {
-    /** @var string */
-    private $tempDir;
+    private string $tempDir;
 
     public function setUp(): void
     {
@@ -87,6 +85,6 @@ public function testReceivesMailArtifacts(): void
     public function testConstructorNoOptions(): void
     {
         $transport = new File();
-        $this->assertSame(FileOptions::class, get_class($transport->getOptions()));
+        $this->assertSame(FileOptions::class, $transport->getOptions()::class);
     }
 }