diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3d665e84..2f5ba8c9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,7 +36,7 @@ jobs:
         run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
 
       - name: Cache composer dependencies
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composer-cache.outputs.dir }}
           # Use composer.json for key, if composer.lock is not committed.
diff --git a/bin/bench_freebusygenerator.php b/bin/bench_freebusygenerator.php
index 89133519..ae859f48 100644
--- a/bin/bench_freebusygenerator.php
+++ b/bin/bench_freebusygenerator.php
@@ -24,9 +24,9 @@
 $bench->parse->stop();
 
 $repeat = 100;
-$start = new \DateTime('2000-01-01');
-$end = new \DateTime('2020-01-01');
-$timeZone = new \DateTimeZone('America/Toronto');
+$start = new DateTime('2000-01-01');
+$end = new DateTime('2020-01-01');
+$timeZone = new DateTimeZone('America/Toronto');
 
 $bench->fb->start();
 
diff --git a/lib/Component.php b/lib/Component.php
index da2c5ebd..95bde3d4 100644
--- a/lib/Component.php
+++ b/lib/Component.php
@@ -2,7 +2,6 @@
 
 namespace Sabre\VObject;
 
-use Sabre\VObject;
 use Sabre\Xml;
 
 /**
@@ -15,7 +14,7 @@
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  *
- * @property VObject\Property\FlatText UID
+ * @property Property\FlatText UID
  */
 class Component extends Node
 {
diff --git a/lib/Component/VCalendar.php b/lib/Component/VCalendar.php
index b317e02c..318492ce 100644
--- a/lib/Component/VCalendar.php
+++ b/lib/Component/VCalendar.php
@@ -20,8 +20,8 @@
  *
  * @property VEvent VEVENT
  * @property VJournal VJOURNAL
- * @property VObject\Property\Text ORG
- * @property VObject\Property\FlatText METHOD
+ * @property Property\Text ORG
+ * @property Property\FlatText METHOD
  */
 class VCalendar extends VObject\Document
 {
@@ -51,21 +51,21 @@ class VCalendar extends VObject\Document
      * List of value-types, and which classes they map to.
      */
     public static array $valueMap = [
-        'BINARY' => VObject\Property\Binary::class,
-        'BOOLEAN' => VObject\Property\Boolean::class,
-        'CAL-ADDRESS' => VObject\Property\ICalendar\CalAddress::class,
-        'DATE' => VObject\Property\ICalendar\Date::class,
-        'DATE-TIME' => VObject\Property\ICalendar\DateTime::class,
-        'DURATION' => VObject\Property\ICalendar\Duration::class,
-        'FLOAT' => VObject\Property\FloatValue::class,
-        'INTEGER' => VObject\Property\IntegerValue::class,
-        'PERIOD' => VObject\Property\ICalendar\Period::class,
-        'RECUR' => VObject\Property\ICalendar\Recur::class,
-        'TEXT' => VObject\Property\Text::class,
-        'TIME' => VObject\Property\Time::class,
-        'UNKNOWN' => VObject\Property\Unknown::class, // jCard / jCal-only.
-        'URI' => VObject\Property\Uri::class,
-        'UTC-OFFSET' => VObject\Property\UtcOffset::class,
+        'BINARY' => Property\Binary::class,
+        'BOOLEAN' => Property\Boolean::class,
+        'CAL-ADDRESS' => Property\ICalendar\CalAddress::class,
+        'DATE' => Property\ICalendar\Date::class,
+        'DATE-TIME' => Property\ICalendar\DateTime::class,
+        'DURATION' => Property\ICalendar\Duration::class,
+        'FLOAT' => Property\FloatValue::class,
+        'INTEGER' => Property\IntegerValue::class,
+        'PERIOD' => Property\ICalendar\Period::class,
+        'RECUR' => Property\ICalendar\Recur::class,
+        'TEXT' => Property\Text::class,
+        'TIME' => Property\Time::class,
+        'UNKNOWN' => Property\Unknown::class, // jCard / jCal-only.
+        'URI' => Property\Uri::class,
+        'UTC-OFFSET' => Property\UtcOffset::class,
     ];
 
     /**
@@ -73,78 +73,78 @@ class VCalendar extends VObject\Document
      */
     public static array $propertyMap = [
         // Calendar properties
-        'CALSCALE' => VObject\Property\FlatText::class,
-        'METHOD' => VObject\Property\FlatText::class,
-        'PRODID' => VObject\Property\FlatText::class,
-        'VERSION' => VObject\Property\FlatText::class,
+        'CALSCALE' => Property\FlatText::class,
+        'METHOD' => Property\FlatText::class,
+        'PRODID' => Property\FlatText::class,
+        'VERSION' => Property\FlatText::class,
 
         // Component properties
-        'ATTACH' => VObject\Property\Uri::class,
-        'CATEGORIES' => VObject\Property\Text::class,
-        'CLASS' => VObject\Property\FlatText::class,
-        'COMMENT' => VObject\Property\FlatText::class,
-        'DESCRIPTION' => VObject\Property\FlatText::class,
-        'GEO' => VObject\Property\FloatValue::class,
-        'LOCATION' => VObject\Property\FlatText::class,
-        'PERCENT-COMPLETE' => VObject\Property\IntegerValue::class,
-        'PRIORITY' => VObject\Property\IntegerValue::class,
-        'RESOURCES' => VObject\Property\Text::class,
-        'STATUS' => VObject\Property\FlatText::class,
-        'SUMMARY' => VObject\Property\FlatText::class,
+        'ATTACH' => Property\Uri::class,
+        'CATEGORIES' => Property\Text::class,
+        'CLASS' => Property\FlatText::class,
+        'COMMENT' => Property\FlatText::class,
+        'DESCRIPTION' => Property\FlatText::class,
+        'GEO' => Property\FloatValue::class,
+        'LOCATION' => Property\FlatText::class,
+        'PERCENT-COMPLETE' => Property\IntegerValue::class,
+        'PRIORITY' => Property\IntegerValue::class,
+        'RESOURCES' => Property\Text::class,
+        'STATUS' => Property\FlatText::class,
+        'SUMMARY' => Property\FlatText::class,
 
         // Date and Time Component Properties
-        'COMPLETED' => VObject\Property\ICalendar\DateTime::class,
-        'DTEND' => VObject\Property\ICalendar\DateTime::class,
-        'DUE' => VObject\Property\ICalendar\DateTime::class,
-        'DTSTART' => VObject\Property\ICalendar\DateTime::class,
-        'DURATION' => VObject\Property\ICalendar\Duration::class,
-        'FREEBUSY' => VObject\Property\ICalendar\Period::class,
-        'TRANSP' => VObject\Property\FlatText::class,
+        'COMPLETED' => Property\ICalendar\DateTime::class,
+        'DTEND' => Property\ICalendar\DateTime::class,
+        'DUE' => Property\ICalendar\DateTime::class,
+        'DTSTART' => Property\ICalendar\DateTime::class,
+        'DURATION' => Property\ICalendar\Duration::class,
+        'FREEBUSY' => Property\ICalendar\Period::class,
+        'TRANSP' => Property\FlatText::class,
 
         // Time Zone Component Properties
-        'TZID' => VObject\Property\FlatText::class,
-        'TZNAME' => VObject\Property\FlatText::class,
-        'TZOFFSETFROM' => VObject\Property\UtcOffset::class,
-        'TZOFFSETTO' => VObject\Property\UtcOffset::class,
-        'TZURL' => VObject\Property\Uri::class,
+        'TZID' => Property\FlatText::class,
+        'TZNAME' => Property\FlatText::class,
+        'TZOFFSETFROM' => Property\UtcOffset::class,
+        'TZOFFSETTO' => Property\UtcOffset::class,
+        'TZURL' => Property\Uri::class,
 
         // Relationship Component Properties
-        'ATTENDEE' => VObject\Property\ICalendar\CalAddress::class,
-        'CONTACT' => VObject\Property\FlatText::class,
-        'ORGANIZER' => VObject\Property\ICalendar\CalAddress::class,
-        'RECURRENCE-ID' => VObject\Property\ICalendar\DateTime::class,
-        'RELATED-TO' => VObject\Property\FlatText::class,
-        'URL' => VObject\Property\Uri::class,
-        'UID' => VObject\Property\FlatText::class,
+        'ATTENDEE' => Property\ICalendar\CalAddress::class,
+        'CONTACT' => Property\FlatText::class,
+        'ORGANIZER' => Property\ICalendar\CalAddress::class,
+        'RECURRENCE-ID' => Property\ICalendar\DateTime::class,
+        'RELATED-TO' => Property\FlatText::class,
+        'URL' => Property\Uri::class,
+        'UID' => Property\FlatText::class,
 
         // Recurrence Component Properties
-        'EXDATE' => VObject\Property\ICalendar\DateTime::class,
-        'RDATE' => VObject\Property\ICalendar\DateTime::class,
-        'RRULE' => VObject\Property\ICalendar\Recur::class,
-        'EXRULE' => VObject\Property\ICalendar\Recur::class, // Deprecated since rfc5545
+        'EXDATE' => Property\ICalendar\DateTime::class,
+        'RDATE' => Property\ICalendar\DateTime::class,
+        'RRULE' => Property\ICalendar\Recur::class,
+        'EXRULE' => Property\ICalendar\Recur::class, // Deprecated since rfc5545
 
         // Alarm Component Properties
-        'ACTION' => VObject\Property\FlatText::class,
-        'REPEAT' => VObject\Property\IntegerValue::class,
-        'TRIGGER' => VObject\Property\ICalendar\Duration::class,
+        'ACTION' => Property\FlatText::class,
+        'REPEAT' => Property\IntegerValue::class,
+        'TRIGGER' => Property\ICalendar\Duration::class,
 
         // Change Management Component Properties
-        'CREATED' => VObject\Property\ICalendar\DateTime::class,
-        'DTSTAMP' => VObject\Property\ICalendar\DateTime::class,
-        'LAST-MODIFIED' => VObject\Property\ICalendar\DateTime::class,
-        'SEQUENCE' => VObject\Property\IntegerValue::class,
+        'CREATED' => Property\ICalendar\DateTime::class,
+        'DTSTAMP' => Property\ICalendar\DateTime::class,
+        'LAST-MODIFIED' => Property\ICalendar\DateTime::class,
+        'SEQUENCE' => Property\IntegerValue::class,
 
         // Request Status
-        'REQUEST-STATUS' => VObject\Property\Text::class,
+        'REQUEST-STATUS' => Property\Text::class,
 
         // Additions from draft-daboo-valarm-extensions-04
-        'ALARM-AGENT' => VObject\Property\Text::class,
-        'ACKNOWLEDGED' => VObject\Property\ICalendar\DateTime::class,
-        'PROXIMITY' => VObject\Property\Text::class,
-        'DEFAULT-ALARM' => VObject\Property\Boolean::class,
+        'ALARM-AGENT' => Property\Text::class,
+        'ACKNOWLEDGED' => Property\ICalendar\DateTime::class,
+        'PROXIMITY' => Property\Text::class,
+        'DEFAULT-ALARM' => Property\Boolean::class,
 
         // Additions from draft-daboo-calendar-availability-05
-        'BUSYTYPE' => VObject\Property\Text::class,
+        'BUSYTYPE' => Property\Text::class,
     ];
 
     /**
@@ -166,10 +166,10 @@ public function getDocumentType(): int
      *
      * @return VObject\Component[]
      */
-    public function getBaseComponents(string $componentName = null): array
+    public function getBaseComponents(?string $componentName = null): array
     {
         $isBaseComponent = function ($component): bool {
-            if (!$component instanceof VObject\Component) {
+            if (!$component instanceof Component) {
                 return false;
             }
             if ('VTIMEZONE' === $component->name) {
@@ -217,10 +217,10 @@ public function getBaseComponents(string $componentName = null): array
      *
      * @return VObject\Component|null
      */
-    public function getBaseComponent(string $componentName = null): ?Component
+    public function getBaseComponent(?string $componentName = null): ?Component
     {
         $isBaseComponent = function ($component): bool {
-            if (!$component instanceof VObject\Component) {
+            if (!$component instanceof Component) {
                 return false;
             }
             if ('VTIMEZONE' === $component->name) {
@@ -275,7 +275,7 @@ public function getBaseComponent(string $componentName = null): ?Component
      * @throws InvalidDataException
      * @throws VObject\Recur\MaxInstancesExceededException
      */
-    public function expand(\DateTimeInterface $start, \DateTimeInterface $end, \DateTimeZone $timeZone = null): VCalendar
+    public function expand(\DateTimeInterface $start, \DateTimeInterface $end, ?\DateTimeZone $timeZone = null): VCalendar
     {
         $newChildren = [];
         $recurringEvents = [];
diff --git a/lib/DateTimeParser.php b/lib/DateTimeParser.php
index 5ce9f207..7e574935 100644
--- a/lib/DateTimeParser.php
+++ b/lib/DateTimeParser.php
@@ -27,7 +27,7 @@ class DateTimeParser
      *
      * @throws InvalidDataException
      */
-    public static function parseDateTime(string $dt, \DateTimeZone $tz = null): \DateTimeImmutable
+    public static function parseDateTime(string $dt, ?\DateTimeZone $tz = null): \DateTimeImmutable
     {
         // Format is YYYYMMDD + "T" + hhmmss
         $result = preg_match('/^([0-9]{4})([0-1][0-9])([0-3][0-9])T([0-2][0-9])([0-5][0-9])([0-5][0-9])([Z]?)$/', $dt, $matches);
@@ -54,7 +54,7 @@ public static function parseDateTime(string $dt, \DateTimeZone $tz = null): \Dat
      *
      * @throws InvalidDataException
      */
-    public static function parseDate(string $date, \DateTimeZone $tz = null): \DateTimeImmutable
+    public static function parseDate(string $date, ?\DateTimeZone $tz = null): \DateTimeImmutable
     {
         // Format is YYYYMMDD
         $result = preg_match('/^([0-9]{4})([0-1][0-9])([0-3][0-9])$/', $date, $matches);
diff --git a/lib/Document.php b/lib/Document.php
index b311987d..6f87b5b9 100644
--- a/lib/Document.php
+++ b/lib/Document.php
@@ -2,8 +2,6 @@
 
 namespace Sabre\VObject;
 
-use Sabre\VObject;
-
 /**
  * Document.
  *
@@ -18,7 +16,7 @@
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  *
- * @property VObject\Property\FlatText VERSION
+ * @property Property\FlatText VERSION
  */
 abstract class Document extends Component
 {
@@ -140,7 +138,7 @@ public function create(string $name)
      * an iCalendar object, this may be something like CALSCALE:GREGORIAN. To
      * ensure that this does not happen, set $defaults to false.
      */
-    public function createComponent(string $name, array $children = null, bool $defaults = true): Component
+    public function createComponent(string $name, ?array $children = null, bool $defaults = true): Component
     {
         $name = strtoupper($name);
         $class = Component::class;
@@ -169,7 +167,7 @@ public function createComponent(string $name, array $children = null, bool $defa
      *
      * @throws InvalidDataException
      */
-    public function createProperty(string $name, $value = null, array $parameters = null, string $valueType = null): Property
+    public function createProperty(string $name, $value = null, ?array $parameters = null, ?string $valueType = null): Property
     {
         // If there's a . in the name, it means it's prefixed by a group name.
         if (false !== ($i = strpos($name, '.'))) {
diff --git a/lib/FreeBusyGenerator.php b/lib/FreeBusyGenerator.php
index 2f222e4e..42482603 100644
--- a/lib/FreeBusyGenerator.php
+++ b/lib/FreeBusyGenerator.php
@@ -72,7 +72,7 @@ class FreeBusyGenerator
      * Check the setTimeRange and setObjects methods for details about the
      * arguments.
      */
-    public function __construct(\DateTimeInterface $start = null, \DateTimeInterface $end = null, $objects = null, \DateTimeZone $timeZone = null)
+    public function __construct(?\DateTimeInterface $start = null, ?\DateTimeInterface $end = null, $objects = null, ?\DateTimeZone $timeZone = null)
     {
         $this->setTimeRange($start, $end);
 
@@ -138,7 +138,7 @@ public function setObjects($objects): void
      *
      * @throws \Exception
      */
-    public function setTimeRange(\DateTimeInterface $start = null, \DateTimeInterface $end = null): void
+    public function setTimeRange(?\DateTimeInterface $start = null, ?\DateTimeInterface $end = null): void
     {
         if (!$start) {
             $start = new \DateTimeImmutable(Settings::$minDate);
diff --git a/lib/ITip/Broker.php b/lib/ITip/Broker.php
index f792fd99..9cbc3f72 100644
--- a/lib/ITip/Broker.php
+++ b/lib/ITip/Broker.php
@@ -113,7 +113,7 @@ class Broker
      * @throws MaxInstancesExceededException
      * @throws NoInstancesException
      */
-    public function processMessage(Message $itipMessage, VCalendar $existingObject = null)
+    public function processMessage(Message $itipMessage, ?VCalendar $existingObject = null)
     {
         // We only support events at the moment.
         if ('VEVENT' !== $itipMessage->component) {
@@ -268,7 +268,7 @@ public function parseEvent($calendar, $userHref, $oldCalendar = null): array
      * This is message from an organizer, and is either a new event
      * invite, or an update to an existing one.
      */
-    protected function processMessageRequest(Message $itipMessage, VCalendar $existingObject = null): ?VCalendar
+    protected function processMessageRequest(Message $itipMessage, ?VCalendar $existingObject = null): ?VCalendar
     {
         if (!$existingObject) {
             // This is a new invite, and we're just going to copy over
@@ -296,7 +296,7 @@ protected function processMessageRequest(Message $itipMessage, VCalendar $existi
      * attendee got removed from an event, or an event got cancelled
      * altogether.
      */
-    protected function processMessageCancel(Message $itipMessage, VCalendar $existingObject = null): ?VCalendar
+    protected function processMessageCancel(Message $itipMessage, ?VCalendar $existingObject = null): ?VCalendar
     {
         if (!$existingObject) {
             // The event didn't exist in the first place, so we're just
@@ -321,7 +321,7 @@ protected function processMessageCancel(Message $itipMessage, VCalendar $existin
      * @throws MaxInstancesExceededException
      * @throws NoInstancesException
      */
-    protected function processMessageReply(Message $itipMessage, VCalendar $existingObject = null): ?VCalendar
+    protected function processMessageReply(Message $itipMessage, ?VCalendar $existingObject = null): ?VCalendar
     {
         // A reply can only be processed based on an existing object.
         // If the object is not available, the reply is ignored.
diff --git a/lib/Property.php b/lib/Property.php
index 53a252fb..574099e6 100644
--- a/lib/Property.php
+++ b/lib/Property.php
@@ -61,7 +61,7 @@ abstract class Property extends Node
      * @param array             $parameters List of parameters
      * @param string|null       $group      The vcard property group
      */
-    public function __construct(Component $root, ?string $name, $value = null, array $parameters = [], string $group = null)
+    public function __construct(Component $root, ?string $name, $value = null, array $parameters = [], ?string $group = null)
     {
         $this->name = $name;
         $this->group = $group;
diff --git a/lib/Property/ICalendar/DateTime.php b/lib/Property/ICalendar/DateTime.php
index 7ee90797..631a73b0 100644
--- a/lib/Property/ICalendar/DateTime.php
+++ b/lib/Property/ICalendar/DateTime.php
@@ -128,7 +128,7 @@ public function isFloating(): bool
      *
      * @throws InvalidDataException
      */
-    public function getDateTime(\DateTimeZone $timeZone = null): ?\DateTimeImmutable
+    public function getDateTime(?\DateTimeZone $timeZone = null): ?\DateTimeImmutable
     {
         $dt = $this->getDateTimes($timeZone);
         if (!$dt) {
@@ -149,7 +149,7 @@ public function getDateTime(\DateTimeZone $timeZone = null): ?\DateTimeImmutable
      *
      * @throws InvalidDataException
      */
-    public function getDateTimes(\DateTimeZone $timeZone = null): array
+    public function getDateTimes(?\DateTimeZone $timeZone = null): array
     {
         // Does the property have a TZID?
         /** @var Property\FlatText $tzid */
diff --git a/lib/Property/Text.php b/lib/Property/Text.php
index c606ad81..c5902905 100644
--- a/lib/Property/Text.php
+++ b/lib/Property/Text.php
@@ -64,7 +64,7 @@ class Text extends Property
      * @param array             $parameters List of parameters
      * @param string|null       $group      The vcard property group
      */
-    public function __construct(Component $root, string $name, $value = null, array $parameters = [], string $group = null)
+    public function __construct(Component $root, string $name, $value = null, array $parameters = [], ?string $group = null)
     {
         // There's two types of multi-valued text properties:
         // 1. multivalue properties.
diff --git a/lib/Recur/EventIterator.php b/lib/Recur/EventIterator.php
index d79cf313..2c93bcf4 100644
--- a/lib/Recur/EventIterator.php
+++ b/lib/Recur/EventIterator.php
@@ -89,7 +89,7 @@ class EventIterator implements \Iterator
      * @throws NoInstancesException
      * @throws InvalidDataException
      */
-    public function __construct($input, string $uid = null, \DateTimeZone $timeZone = null)
+    public function __construct($input, ?string $uid = null, ?\DateTimeZone $timeZone = null)
     {
         if (is_null($timeZone)) {
             $timeZone = new \DateTimeZone('UTC');
diff --git a/lib/Splitter/ICalendar.php b/lib/Splitter/ICalendar.php
index ccf0d1ad..79f0bd44 100644
--- a/lib/Splitter/ICalendar.php
+++ b/lib/Splitter/ICalendar.php
@@ -46,7 +46,7 @@ public function __construct($input, int $options = 0)
     {
         $data = VObject\Reader::read($input, $options);
 
-        if (!$data instanceof VObject\Component\VCalendar) {
+        if (!$data instanceof VCalendar) {
             throw new VObject\ParseException('Supplied input could not be parsed as VCALENDAR.');
         }
 
diff --git a/lib/Splitter/VCard.php b/lib/Splitter/VCard.php
index e63ae837..40775a33 100644
--- a/lib/Splitter/VCard.php
+++ b/lib/Splitter/VCard.php
@@ -61,7 +61,7 @@ public function getNext(): ?Component
         try {
             $object = $this->parser->parse();
 
-            if (!$object instanceof VObject\Component\VCard) {
+            if (!$object instanceof Component\VCard) {
                 throw new VObject\ParseException('The supplied input contained non-VCARD data.');
             }
         } catch (VObject\EofException $e) {
diff --git a/lib/TimeZoneUtil.php b/lib/TimeZoneUtil.php
index 8c2a374f..2cd45857 100644
--- a/lib/TimeZoneUtil.php
+++ b/lib/TimeZoneUtil.php
@@ -72,7 +72,7 @@ private function addFinder(string $key, TimezoneFinder $finder): void
      * Alternatively, if $failIfUncertain is set to true, it will throw an
      * exception if we cannot accurately determine the timezone.
      */
-    private function findTimeZone(string $tzid, Component $vcalendar = null, bool $failIfUncertain = false): \DateTimeZone
+    private function findTimeZone(string $tzid, ?Component $vcalendar = null, bool $failIfUncertain = false): \DateTimeZone
     {
         foreach ($this->timezoneFinders as $timezoneFinder) {
             $timezone = $timezoneFinder->find($tzid, $failIfUncertain);
@@ -117,7 +117,7 @@ public static function addTimezoneFinder(string $key, TimezoneFinder $finder): v
         self::getInstance()->addFinder($key, $finder);
     }
 
-    public static function getTimeZone(string $tzid, Component $vcalendar = null, bool $failIfUncertain = false): \DateTimeZone
+    public static function getTimeZone(string $tzid, ?Component $vcalendar = null, bool $failIfUncertain = false): \DateTimeZone
     {
         return self::getInstance()->findTimeZone($tzid, $vcalendar, $failIfUncertain);
     }
diff --git a/lib/VCardConverter.php b/lib/VCardConverter.php
index 88d74602..74901fc1 100644
--- a/lib/VCardConverter.php
+++ b/lib/VCardConverter.php
@@ -93,8 +93,8 @@ protected function convertProperty(Component\VCard $input, Component\VCard $outp
         );
 
         if (Document::VCARD30 === $targetVersion) {
-            if ($property instanceof Property\Uri && in_array($property->name, ['PHOTO', 'LOGO', 'SOUND'])) {
-                /** @var Property\Uri $newProperty */
+            if ($property instanceof Uri && in_array($property->name, ['PHOTO', 'LOGO', 'SOUND'])) {
+                /** @var Uri $newProperty */
                 $newProperty = $this->convertUriToBinary($output, $newProperty);
             } elseif ($property instanceof Property\VCard\DateAndOrTime) {
                 // In vCard 4, the birth year may be optional. This is not the
@@ -153,8 +153,8 @@ protected function convertProperty(Component\VCard $input, Component\VCard $outp
                 return;
             }
 
-            if ($property instanceof Property\Binary) {
-                /** @var Property\Binary $newProperty */
+            if ($property instanceof Binary) {
+                /** @var Binary $newProperty */
                 $newProperty = $this->convertBinaryToUri($output, $newProperty, $parameters);
             } elseif ($property instanceof Property\VCard\DateAndOrTime && isset($parameters['X-APPLE-OMIT-YEAR'])) {
                 // If a property such as BDAY contained 'X-APPLE-OMIT-YEAR',
@@ -256,7 +256,7 @@ protected function convertProperty(Component\VCard $input, Component\VCard $outp
      *
      * @throws InvalidDataException
      */
-    protected function convertBinaryToUri(Component\VCard $output, Property\Binary $newProperty, array &$parameters): Uri
+    protected function convertBinaryToUri(Component\VCard $output, Binary $newProperty, array &$parameters): Uri
     {
         $value = $newProperty->getValue();
         /** @var Uri $newProperty */
@@ -308,7 +308,7 @@ protected function convertBinaryToUri(Component\VCard $output, Property\Binary $
      *
      * @throws InvalidDataException
      */
-    protected function convertUriToBinary(Component\VCard $output, Property\Uri $newProperty): Property
+    protected function convertUriToBinary(Component\VCard $output, Uri $newProperty): Property
     {
         $value = $newProperty->getValue();
 
diff --git a/tests/VObject/Component/VCalendarTest.php b/tests/VObject/Component/VCalendarTest.php
index 1893a9ac..bde6a4fa 100644
--- a/tests/VObject/Component/VCalendarTest.php
+++ b/tests/VObject/Component/VCalendarTest.php
@@ -756,7 +756,7 @@ public function testCalDAVMETHOD(): void
         );
     }
 
-    public function assertValidate($ics, $options, $expectedLevel, string $expectedMessage = null): void
+    public function assertValidate($ics, $options, $expectedLevel, ?string $expectedMessage = null): void
     {
         $vcal = VObject\Reader::read($ics);
         $result = $vcal->validate($options);
@@ -764,7 +764,7 @@ public function assertValidate($ics, $options, $expectedLevel, string $expectedM
         self::assertValidateResult($result, $expectedLevel, $expectedMessage);
     }
 
-    public function assertValidateResult($input, $expectedLevel, string $expectedMessage = null): void
+    public function assertValidateResult($input, $expectedLevel, ?string $expectedMessage = null): void
     {
         $messages = [];
         foreach ($input as $warning) {
diff --git a/tests/VObject/Component/VCardTest.php b/tests/VObject/Component/VCardTest.php
index b71b3085..3851d97d 100644
--- a/tests/VObject/Component/VCardTest.php
+++ b/tests/VObject/Component/VCardTest.php
@@ -283,7 +283,7 @@ public function testVCard21NoCardDAV(): void
         );
     }
 
-    public function assertValidate($vcf, $options, int $expectedLevel, string $expectedMessage = null): void
+    public function assertValidate($vcf, $options, int $expectedLevel, ?string $expectedMessage = null): void
     {
         $vcal = VObject\Reader::read($vcf);
         $result = $vcal->validate($options);
@@ -291,7 +291,7 @@ public function assertValidate($vcf, $options, int $expectedLevel, string $expec
         self::assertValidateResult($result, $expectedLevel, $expectedMessage);
     }
 
-    public function assertValidateResult($input, int $expectedLevel, string $expectedMessage = null): void
+    public function assertValidateResult($input, int $expectedLevel, ?string $expectedMessage = null): void
     {
         $messages = [];
         foreach ($input as $warning) {
diff --git a/tests/VObject/Component/VFreeBusyTest.php b/tests/VObject/Component/VFreeBusyTest.php
index f3a521f9..f2f97ebe 100644
--- a/tests/VObject/Component/VFreeBusyTest.php
+++ b/tests/VObject/Component/VFreeBusyTest.php
@@ -3,7 +3,6 @@
 namespace Sabre\VObject\Component;
 
 use PHPUnit\Framework\TestCase;
-use Sabre\VObject;
 use Sabre\VObject\Reader;
 
 class VFreeBusyTest extends TestCase
@@ -23,7 +22,7 @@ public function testIsFree(): void
 END:VCALENDAR
 BLA;
 
-        $obj = VObject\Reader::read($input);
+        $obj = Reader::read($input);
         $vfb = $obj->VFREEBUSY;
 
         $tz = new \DateTimeZone('UTC');
diff --git a/tests/VObject/ComponentTest.php b/tests/VObject/ComponentTest.php
index 4a247d90..c4848098 100644
--- a/tests/VObject/ComponentTest.php
+++ b/tests/VObject/ComponentTest.php
@@ -463,7 +463,7 @@ public function testRemoveNotFound(): void
      */
     public function testValidateRules(array $componentList, int $errorCount): void
     {
-        $vcard = new Component\VCard();
+        $vcard = new VCard();
 
         $component = new FakeComponent($vcard, 'Hi', [], false);
         foreach ($componentList as $v) {
@@ -475,7 +475,7 @@ public function testValidateRules(array $componentList, int $errorCount): void
 
     public function testValidateRepair(): void
     {
-        $vcard = new Component\VCard();
+        $vcard = new VCard();
 
         $component = new FakeComponent($vcard, 'Hi', [], false);
         $component->validate(Component::REPAIR);
@@ -484,7 +484,7 @@ public function testValidateRepair(): void
 
     public function testValidateRepairShouldNotDeduplicatePropertiesWhenValuesDiffer(): void
     {
-        $vcard = new Component\VCard();
+        $vcard = new VCard();
 
         $component = new FakeComponent($vcard, 'WithDuplicateGIR', []);
         $component->add('BAZ', 'BAZ');
@@ -500,7 +500,7 @@ public function testValidateRepairShouldNotDeduplicatePropertiesWhenValuesDiffer
 
     public function testValidateRepairShouldNotDeduplicatePropertiesWhenParametersDiffer(): void
     {
-        $vcard = new Component\VCard();
+        $vcard = new VCard();
 
         $component = new FakeComponent($vcard, 'WithDuplicateGIR', []);
         $component->add('BAZ', 'BAZ');
@@ -516,7 +516,7 @@ public function testValidateRepairShouldNotDeduplicatePropertiesWhenParametersDi
 
     public function testValidateRepairShouldDeduplicatePropertiesWhenValuesAndParametersAreEqual(): void
     {
-        $vcard = new Component\VCard();
+        $vcard = new VCard();
 
         $component = new FakeComponent($vcard, 'WithDuplicateGIR', []);
         $component->add('BAZ', 'BAZ');
@@ -532,7 +532,7 @@ public function testValidateRepairShouldDeduplicatePropertiesWhenValuesAndParame
 
     public function testValidateRepairShouldDeduplicatePropertiesWhenValuesAreEqual(): void
     {
-        $vcard = new Component\VCard();
+        $vcard = new VCard();
 
         $component = new FakeComponent($vcard, 'WithDuplicateGIR', []);
         $component->add('BAZ', 'BAZ');
diff --git a/tests/VObject/EmptyParameterTest.php b/tests/VObject/EmptyParameterTest.php
index ab197ab3..6739f104 100644
--- a/tests/VObject/EmptyParameterTest.php
+++ b/tests/VObject/EmptyParameterTest.php
@@ -21,7 +21,7 @@ public function testRead(): void
         $vcard = Reader::read($input);
 
         self::assertInstanceOf(Component\VCard::class, $vcard);
-        $vcard = $vcard->convert(\Sabre\VObject\Document::VCARD30);
+        $vcard = $vcard->convert(Document::VCARD30);
         $vcard = $vcard->serialize();
 
         $converted = Reader::read($vcard);
diff --git a/tests/VObject/FreeBusyGeneratorTest.php b/tests/VObject/FreeBusyGeneratorTest.php
index 47283eaf..a4946cc1 100644
--- a/tests/VObject/FreeBusyGeneratorTest.php
+++ b/tests/VObject/FreeBusyGeneratorTest.php
@@ -46,7 +46,7 @@ public function testInvalidArg(): void
      *
      * @throws ParseException
      */
-    public function assertFreeBusyReport(string $expected, $input, \DateTimeZone $timeZone = null, string $vavailability = null): void
+    public function assertFreeBusyReport(string $expected, $input, ?\DateTimeZone $timeZone = null, ?string $vavailability = null): void
     {
         $gen = new FreeBusyGenerator(
             new \DateTime('20110101T110000Z', new \DateTimeZone('UTC')),
diff --git a/tests/VObject/Recur/RRuleIteratorTest.php b/tests/VObject/Recur/RRuleIteratorTest.php
index 2814df66..519f5122 100644
--- a/tests/VObject/Recur/RRuleIteratorTest.php
+++ b/tests/VObject/Recur/RRuleIteratorTest.php
@@ -1072,7 +1072,7 @@ public function testIteratorFunctions(): void
         );
     }
 
-    public function parse($rule, string $start, array $expected, string $fastForward = null, string $tz = 'UTC', bool $runTillTheEnd = false): void
+    public function parse($rule, string $start, array $expected, ?string $fastForward = null, string $tz = 'UTC', bool $runTillTheEnd = false): void
     {
         $dt = new \DateTime($start, new \DateTimeZone($tz));
         $parser = new RRuleIterator($rule, $dt);
diff --git a/tests/VObject/VCardConverterTest.php b/tests/VObject/VCardConverterTest.php
index 9db0ad56..db778261 100644
--- a/tests/VObject/VCardConverterTest.php
+++ b/tests/VObject/VCardConverterTest.php
@@ -554,7 +554,7 @@ public function testNoLabel(): void
 
         $vcard = Reader::read($input);
 
-        self::assertInstanceOf(Component\VCard::class, $vcard);
+        self::assertInstanceOf(VCard::class, $vcard);
         /** @var VCard $vcard */
         $vcard = $vcard->convert(Document::VCARD40);
         $vcard = $vcard->serialize();