diff --git a/src/PhpSpreadsheet/Calculation/Engine/BranchPruner.php b/src/PhpSpreadsheet/Calculation/Engine/BranchPruner.php
index 29bf85280..09a1a251d 100644
--- a/src/PhpSpreadsheet/Calculation/Engine/BranchPruner.php
+++ b/src/PhpSpreadsheet/Calculation/Engine/BranchPruner.php
@@ -47,20 +47,11 @@ class BranchPruner
      */
     protected $braceDepthMap = [];
 
-    /**
-     * @var null|string
-     */
-    protected $currentCondition;
+    protected ?string $currentCondition = null;
 
-    /**
-     * @var null|string
-     */
-    protected $currentOnlyIf;
+    protected ?string $currentOnlyIf = null;
 
-    /**
-     * @var null|string
-     */
-    protected $currentOnlyIfNot;
+    protected ?string $currentOnlyIfNot = null;
 
     /**
      * @var null|string
diff --git a/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/InterestAndPrincipal.php b/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/InterestAndPrincipal.php
index f21eb55a3..ea9abb982 100644
--- a/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/InterestAndPrincipal.php
+++ b/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/InterestAndPrincipal.php
@@ -6,8 +6,7 @@ use PhpOffice\PhpSpreadsheet\Calculation\Financial\Constants as FinancialConstan
 
 class InterestAndPrincipal
 {
-    /** @var float */
-    protected $interest;
+    protected float $interest;
 
     protected float $principal;
 
diff --git a/src/PhpSpreadsheet/Cell/CellAddress.php b/src/PhpSpreadsheet/Cell/CellAddress.php
index 7ec25724e..fb8ca9fbb 100644
--- a/src/PhpSpreadsheet/Cell/CellAddress.php
+++ b/src/PhpSpreadsheet/Cell/CellAddress.php
@@ -9,25 +9,13 @@ class CellAddress
 {
     protected ?\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $worksheet;
 
-    /**
-     * @var string
-     */
-    protected $cellAddress;
+    protected string $cellAddress;
 
-    /**
-     * @var string
-     */
-    protected $columnName;
+    protected string $columnName = '';
 
-    /**
-     * @var int
-     */
-    protected $columnId;
+    protected int $columnId;
 
-    /**
-     * @var int
-     */
-    protected $rowId;
+    protected int $rowId;
 
     public function __construct(string $cellAddress, ?Worksheet $worksheet = null)
     {
diff --git a/src/PhpSpreadsheet/Cell/ColumnRange.php b/src/PhpSpreadsheet/Cell/ColumnRange.php
index 7461e6736..9c0a000e5 100644
--- a/src/PhpSpreadsheet/Cell/ColumnRange.php
+++ b/src/PhpSpreadsheet/Cell/ColumnRange.php
@@ -8,15 +8,9 @@ class ColumnRange implements AddressRange
 {
     protected ?\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $worksheet;
 
-    /**
-     * @var int
-     */
-    protected $from;
+    protected int $from;
 
-    /**
-     * @var int
-     */
-    protected $to;
+    protected int $to;
 
     public function __construct(string $from, ?string $to = null, ?Worksheet $worksheet = null)
     {
diff --git a/src/PhpSpreadsheet/Cell/DataValidation.php b/src/PhpSpreadsheet/Cell/DataValidation.php
index 969c65be0..21d41c8dc 100644
--- a/src/PhpSpreadsheet/Cell/DataValidation.php
+++ b/src/PhpSpreadsheet/Cell/DataValidation.php
@@ -480,8 +480,7 @@ class DataValidation
         }
     }
 
-    /** @var ?string */
-    private $sqref;
+    private ?string $sqref = null;
 
     public function getSqref(): ?string
     {
diff --git a/src/PhpSpreadsheet/Cell/RowRange.php b/src/PhpSpreadsheet/Cell/RowRange.php
index 8aa642551..0ba10ca6b 100644
--- a/src/PhpSpreadsheet/Cell/RowRange.php
+++ b/src/PhpSpreadsheet/Cell/RowRange.php
@@ -8,15 +8,9 @@ class RowRange implements AddressRange
 {
     protected ?\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $worksheet;
 
-    /**
-     * @var int
-     */
-    protected $from;
+    protected int $from;
 
-    /**
-     * @var int
-     */
-    protected $to;
+    protected int $to;
 
     public function __construct(int $from, ?int $to = null, ?Worksheet $worksheet = null)
     {
diff --git a/src/PhpSpreadsheet/CellReferenceHelper.php b/src/PhpSpreadsheet/CellReferenceHelper.php
index a89329bf9..2bb0c8a2d 100644
--- a/src/PhpSpreadsheet/CellReferenceHelper.php
+++ b/src/PhpSpreadsheet/CellReferenceHelper.php
@@ -7,10 +7,7 @@ use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
 
 class CellReferenceHelper
 {
-    /**
-     * @var string
-     */
-    protected $beforeCellAddress;
+    protected string $beforeCellAddress;
 
     protected int $beforeColumn;
 
diff --git a/src/PhpSpreadsheet/Chart/Axis.php b/src/PhpSpreadsheet/Chart/Axis.php
index 866014022..b9c7475af 100644
--- a/src/PhpSpreadsheet/Chart/Axis.php
+++ b/src/PhpSpreadsheet/Chart/Axis.php
@@ -26,17 +26,13 @@ class Axis extends Properties
 
     /**
      * Chart Major Gridlines as.
-     *
-     * @var ?GridLines
      */
-    private $majorGridlines;
+    private ?\PhpOffice\PhpSpreadsheet\Chart\GridLines $majorGridlines = null;
 
     /**
      * Chart Minor Gridlines as.
-     *
-     * @var ?GridLines
      */
-    private $minorGridlines;
+    private ?\PhpOffice\PhpSpreadsheet\Chart\GridLines $minorGridlines = null;
 
     /**
      * Axis Number.
@@ -49,11 +45,9 @@ class Axis extends Properties
         'numeric' => null,
     ];
 
-    /** @var string */
-    private $axisType = '';
+    private string $axisType = '';
 
-    /** @var ?AxisText */
-    private $axisText;
+    private ?\PhpOffice\PhpSpreadsheet\Chart\AxisText $axisText = null;
 
     /**
      * Axis Options.
@@ -265,8 +259,7 @@ class Axis extends Properties
         return $this->getLineColorProperty($propertyName);
     }
 
-    /** @var string */
-    private $crossBetween = ''; // 'between' or 'midCat' might be better
+    private string $crossBetween = ''; // 'between' or 'midCat' might be better
 
     public function setCrossBetween(string $crossBetween): self
     {
diff --git a/src/PhpSpreadsheet/Chart/AxisText.php b/src/PhpSpreadsheet/Chart/AxisText.php
index 796be04a4..c3b2d3b24 100644
--- a/src/PhpSpreadsheet/Chart/AxisText.php
+++ b/src/PhpSpreadsheet/Chart/AxisText.php
@@ -6,8 +6,7 @@ use PhpOffice\PhpSpreadsheet\Style\Font;
 
 class AxisText extends Properties
 {
-    /** @var ?int */
-    private $rotation;
+    private ?int $rotation = null;
 
     private \PhpOffice\PhpSpreadsheet\Style\Font $font;
 
diff --git a/src/PhpSpreadsheet/Chart/Chart.php b/src/PhpSpreadsheet/Chart/Chart.php
index b390e5ab9..9f78962a4 100644
--- a/src/PhpSpreadsheet/Chart/Chart.php
+++ b/src/PhpSpreadsheet/Chart/Chart.php
@@ -16,10 +16,8 @@ class Chart
 
     /**
      * Worksheet.
-     *
-     * @var ?Worksheet
      */
-    private $worksheet;
+    private ?\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $worksheet = null;
 
     /**
      * Chart Title.
@@ -93,10 +91,8 @@ class Chart
 
     /**
      * Bottom-Right Cell Position.
-     *
-     * @var string
      */
-    private $bottomRightCellRef = '';
+    private string $bottomRightCellRef = '';
 
     /**
      * Bottom-Right X-Offset.
@@ -112,17 +108,13 @@ class Chart
      */
     private $bottomRightYOffset = 10;
 
-    /** @var ?int */
-    private $rotX;
+    private ?int $rotX = null;
 
-    /** @var ?int */
-    private $rotY;
+    private ?int $rotY = null;
 
-    /** @var ?int */
-    private $rAngAx;
+    private ?int $rAngAx = null;
 
-    /** @var ?int */
-    private $perspective;
+    private ?int $perspective = null;
 
     /** @var bool */
     private $oneCellAnchor = false;
diff --git a/src/PhpSpreadsheet/Chart/ChartColor.php b/src/PhpSpreadsheet/Chart/ChartColor.php
index 87f310200..df08adb5d 100644
--- a/src/PhpSpreadsheet/Chart/ChartColor.php
+++ b/src/PhpSpreadsheet/Chart/ChartColor.php
@@ -15,17 +15,13 @@ class ChartColor
         self::EXCEL_COLOR_TYPE_STANDARD,
     ];
 
-    /** @var string */
-    private $value = '';
+    private string $value = '';
 
-    /** @var string */
-    private $type = '';
+    private string $type = '';
 
-    /** @var ?int */
-    private $alpha;
+    private ?int $alpha = null;
 
-    /** @var ?int */
-    private $brightness;
+    private ?int $brightness = null;
 
     /**
      * @param string|string[] $value
diff --git a/src/PhpSpreadsheet/Chart/DataSeriesValues.php b/src/PhpSpreadsheet/Chart/DataSeriesValues.php
index b8c9f45a3..31a49d949 100644
--- a/src/PhpSpreadsheet/Chart/DataSeriesValues.php
+++ b/src/PhpSpreadsheet/Chart/DataSeriesValues.php
@@ -83,8 +83,7 @@ class DataSeriesValues extends Properties
     /** @var bool */
     private $bubble3D = false;
 
-    /** @var ?Layout */
-    private $labelLayout;
+    private ?\PhpOffice\PhpSpreadsheet\Chart\Layout $labelLayout = null;
 
     /** @var TrendLine[] */
     private $trendLines = [];
diff --git a/src/PhpSpreadsheet/Chart/Legend.php b/src/PhpSpreadsheet/Chart/Legend.php
index 6e31a5eaa..9d21ee51a 100644
--- a/src/PhpSpreadsheet/Chart/Legend.php
+++ b/src/PhpSpreadsheet/Chart/Legend.php
@@ -50,8 +50,7 @@ class Legend
 
     private \PhpOffice\PhpSpreadsheet\Chart\ChartColor $fillColor;
 
-    /** @var ?AxisText */
-    private $legendText;
+    private ?\PhpOffice\PhpSpreadsheet\Chart\AxisText $legendText = null;
 
     /**
      * Create a new Legend.
diff --git a/src/PhpSpreadsheet/Chart/PlotArea.php b/src/PhpSpreadsheet/Chart/PlotArea.php
index e6c816308..168de8b13 100644
--- a/src/PhpSpreadsheet/Chart/PlotArea.php
+++ b/src/PhpSpreadsheet/Chart/PlotArea.php
@@ -25,10 +25,8 @@ class PlotArea
 
     /**
      * PlotArea Gradient Angle.
-     *
-     * @var ?float
      */
-    private $gradientFillAngle;
+    private ?float $gradientFillAngle = null;
 
     /**
      * PlotArea Layout.
@@ -162,8 +160,7 @@ class PlotArea
         return $this->gradientFillStops;
     }
 
-    /** @var ?int */
-    private $gapWidth;
+    private ?int $gapWidth = null;
 
     /** @var bool */
     private $useUpBars = false;
diff --git a/src/PhpSpreadsheet/Chart/Properties.php b/src/PhpSpreadsheet/Chart/Properties.php
index a97b803bd..f6c953122 100644
--- a/src/PhpSpreadsheet/Chart/Properties.php
+++ b/src/PhpSpreadsheet/Chart/Properties.php
@@ -125,8 +125,7 @@ abstract class Properties
     /** @var ?float */
     protected $glowSize;
 
-    /** @var ChartColor */
-    protected $glowColor;
+    protected \PhpOffice\PhpSpreadsheet\Chart\ChartColor $glowColor;
 
     /** @var array */
     protected $softEdges = [
@@ -731,8 +730,7 @@ abstract class Properties
         return $array;
     }
 
-    /** @var ChartColor */
-    protected $lineColor;
+    protected \PhpOffice\PhpSpreadsheet\Chart\ChartColor $lineColor;
 
     /** @var array */
     protected $lineStyleProperties = [
diff --git a/src/PhpSpreadsheet/Chart/TrendLine.php b/src/PhpSpreadsheet/Chart/TrendLine.php
index 75a5896c9..7ea2bde81 100644
--- a/src/PhpSpreadsheet/Chart/TrendLine.php
+++ b/src/PhpSpreadsheet/Chart/TrendLine.php
@@ -19,8 +19,7 @@ class TrendLine extends Properties
         self::TRENDLINE_MOVING_AVG,
     ];
 
-    /** @var string */
-    private $trendLineType = 'linear'; // TRENDLINE_LINEAR
+    private string $trendLineType = 'linear'; // TRENDLINE_LINEAR
 
     /** @var int */
     private $order = 2;
@@ -34,8 +33,7 @@ class TrendLine extends Properties
     /** @var bool */
     private $dispEq = false;
 
-    /** @var string */
-    private $name = '';
+    private string $name = '';
 
     /** @var float */
     private $backward = 0.0;
diff --git a/src/PhpSpreadsheet/Comment.php b/src/PhpSpreadsheet/Comment.php
index 201f4348b..4759fcbe6 100644
--- a/src/PhpSpreadsheet/Comment.php
+++ b/src/PhpSpreadsheet/Comment.php
@@ -24,24 +24,18 @@ class Comment implements IComparable
 
     /**
      * Comment width (CSS style, i.e. XXpx or YYpt).
-     *
-     * @var string
      */
-    private $width = '96pt';
+    private string $width = '96pt';
 
     /**
      * Left margin (CSS style, i.e. XXpx or YYpt).
-     *
-     * @var string
      */
-    private $marginLeft = '59.25pt';
+    private string $marginLeft = '59.25pt';
 
     /**
      * Top margin (CSS style, i.e. XXpx or YYpt).
-     *
-     * @var string
      */
-    private $marginTop = '1.5pt';
+    private string $marginTop = '1.5pt';
 
     /**
      * Visible.
@@ -52,10 +46,8 @@ class Comment implements IComparable
 
     /**
      * Comment height (CSS style, i.e. XXpx or YYpt).
-     *
-     * @var string
      */
-    private $height = '55.5pt';
+    private string $height = '55.5pt';
 
     /**
      * Comment fill color.
diff --git a/src/PhpSpreadsheet/Document/Properties.php b/src/PhpSpreadsheet/Document/Properties.php
index 5049c956f..a1c29fedb 100644
--- a/src/PhpSpreadsheet/Document/Properties.php
+++ b/src/PhpSpreadsheet/Document/Properties.php
@@ -25,17 +25,13 @@ class Properties
 
     /**
      * Creator.
-     *
-     * @var string
      */
-    private $creator = 'Unknown Creator';
+    private string $creator = 'Unknown Creator';
 
     /**
      * LastModifiedBy.
-     *
-     * @var string
      */
-    private $lastModifiedBy;
+    private string $lastModifiedBy;
 
     /**
      * Created.
@@ -49,52 +45,38 @@ class Properties
 
     /**
      * Title.
-     *
-     * @var string
      */
-    private $title = 'Untitled Spreadsheet';
+    private string $title = 'Untitled Spreadsheet';
 
     /**
      * Description.
-     *
-     * @var string
      */
-    private $description = '';
+    private string $description = '';
 
     /**
      * Subject.
-     *
-     * @var string
      */
-    private $subject = '';
+    private string $subject = '';
 
     /**
      * Keywords.
-     *
-     * @var string
      */
-    private $keywords = '';
+    private string $keywords = '';
 
     /**
      * Category.
-     *
-     * @var string
      */
-    private $category = '';
+    private string $category = '';
 
     /**
      * Manager.
-     *
-     * @var string
      */
-    private $manager = '';
+    private string $manager = '';
 
     /**
      * Company.
-     *
-     * @var string
      */
-    private $company = '';
+    private string $company = '';
 
     /**
      * Custom Properties.
diff --git a/src/PhpSpreadsheet/Document/Security.php b/src/PhpSpreadsheet/Document/Security.php
index 1f5625689..a97017b68 100644
--- a/src/PhpSpreadsheet/Document/Security.php
+++ b/src/PhpSpreadsheet/Document/Security.php
@@ -29,17 +29,13 @@ class Security
 
     /**
      * RevisionsPassword.
-     *
-     * @var string
      */
-    private $revisionsPassword = '';
+    private string $revisionsPassword = '';
 
     /**
      * WorkbookPassword.
-     *
-     * @var string
      */
-    private $workbookPassword = '';
+    private string $workbookPassword = '';
 
     /**
      * Create a new Document Security instance.
diff --git a/src/PhpSpreadsheet/Reader/BaseReader.php b/src/PhpSpreadsheet/Reader/BaseReader.php
index aa380aa95..da79c3a47 100644
--- a/src/PhpSpreadsheet/Reader/BaseReader.php
+++ b/src/PhpSpreadsheet/Reader/BaseReader.php
@@ -54,10 +54,7 @@ abstract class BaseReader implements IReader
     /** @var resource */
     protected $fileHandle;
 
-    /**
-     * @var ?XmlScanner
-     */
-    protected $securityScanner;
+    protected ?\PhpOffice\PhpSpreadsheet\Reader\Security\XmlScanner $securityScanner = null;
 
     public function __construct()
     {
diff --git a/src/PhpSpreadsheet/Reader/Csv.php b/src/PhpSpreadsheet/Reader/Csv.php
index be9a2a32c..02134abfd 100644
--- a/src/PhpSpreadsheet/Reader/Csv.php
+++ b/src/PhpSpreadsheet/Reader/Csv.php
@@ -32,10 +32,8 @@ class Csv extends BaseReader
 
     /**
      * Input encoding.
-     *
-     * @var string
      */
-    private $inputEncoding = 'UTF-8';
+    private string $inputEncoding = 'UTF-8';
 
     /**
      * Fallback encoding if guess strikes out.
@@ -46,17 +44,13 @@ class Csv extends BaseReader
 
     /**
      * Delimiter.
-     *
-     * @var ?string
      */
-    private $delimiter;
+    private ?string $delimiter = null;
 
     /**
      * Enclosure.
-     *
-     * @var string
      */
-    private $enclosure = '"';
+    private string $enclosure = '"';
 
     /**
      * Sheet index to read.
@@ -74,10 +68,8 @@ class Csv extends BaseReader
 
     /**
      * The character that can escape the enclosure.
-     *
-     * @var string
      */
-    private $escapeCharacter = '\\';
+    private string $escapeCharacter = '\\';
 
     /**
      * Callback for setting defaults in construction.
diff --git a/src/PhpSpreadsheet/Reader/Xls.php b/src/PhpSpreadsheet/Reader/Xls.php
index 938280850..4eb96b4c2 100644
--- a/src/PhpSpreadsheet/Reader/Xls.php
+++ b/src/PhpSpreadsheet/Reader/Xls.php
@@ -219,10 +219,8 @@ class Xls extends BaseReader
     /**
      * Codepage set in the Excel file being read. Only important for BIFF5 (Excel 5.0 - Excel 95)
      * For BIFF8 (Excel 97 - Excel 2003) this will always have the value 'UTF-16LE'.
-     *
-     * @var string
      */
-    private $codepage = '';
+    private string $codepage = '';
 
     /**
      * Shared formats.
diff --git a/src/PhpSpreadsheet/Shared/Escher/DgContainer.php b/src/PhpSpreadsheet/Shared/Escher/DgContainer.php
index 51c6860cb..73496cb4e 100644
--- a/src/PhpSpreadsheet/Shared/Escher/DgContainer.php
+++ b/src/PhpSpreadsheet/Shared/Escher/DgContainer.php
@@ -8,20 +8,15 @@ class DgContainer
 {
     /**
      * Drawing index, 1-based.
-     *
-     * @var ?int
      */
-    private $dgId;
+    private ?int $dgId = null;
 
     /**
      * Last shape index in this drawing.
-     *
-     * @var ?int
      */
-    private $lastSpId;
+    private ?int $lastSpId = null;
 
-    /** @var ?DgContainer\SpgrContainer */
-    private $spgrContainer;
+    private ?\PhpOffice\PhpSpreadsheet\Shared\Escher\DgContainer\SpgrContainer $spgrContainer = null;
 
     public function getDgId(): ?int
     {
diff --git a/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalDataBar.php b/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalDataBar.php
index c5c36aeb3..e0a511f16 100644
--- a/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalDataBar.php
+++ b/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalDataBar.php
@@ -9,21 +9,13 @@ class ConditionalDataBar
     /** @var null|bool */
     private $showValue;
 
-    /** <dataBar> children */
+    private ?\PhpOffice\PhpSpreadsheet\Style\ConditionalFormatting\ConditionalFormatValueObject $minimumConditionalFormatValueObject = null;
 
-    /** @var ?ConditionalFormatValueObject */
-    private $minimumConditionalFormatValueObject;
+    private ?\PhpOffice\PhpSpreadsheet\Style\ConditionalFormatting\ConditionalFormatValueObject $maximumConditionalFormatValueObject = null;
 
-    /** @var ?ConditionalFormatValueObject */
-    private $maximumConditionalFormatValueObject;
+    private string $color = '';
 
-    /** @var string */
-    private $color;
-
-    /** <extLst> */
-
-    /** @var ?ConditionalFormattingRuleExtension */
-    private $conditionalFormattingRuleExt;
+    private ?\PhpOffice\PhpSpreadsheet\Style\ConditionalFormatting\ConditionalFormattingRuleExtension $conditionalFormattingRuleExt = null;
 
     /**
      * @return null|bool
diff --git a/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalFormattingRuleExtension.php b/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalFormattingRuleExtension.php
index a2a57e3e8..a35426a1c 100644
--- a/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalFormattingRuleExtension.php
+++ b/src/PhpSpreadsheet/Style/ConditionalFormatting/ConditionalFormattingRuleExtension.php
@@ -14,13 +14,10 @@ class ConditionalFormattingRuleExtension
     /** @var string Conditional Formatting Rule */
     private string $cfRule;
 
-    /** <conditionalFormatting> children */
-
-    /** @var ConditionalDataBarExtension */
-    private $dataBar;
+    private \PhpOffice\PhpSpreadsheet\Style\ConditionalFormatting\ConditionalDataBarExtension $dataBar;
 
     /** @var string Sequence of References */
-    private $sqref;
+    private string $sqref = '';
 
     /**
      * ConditionalFormattingRuleExtension constructor.
diff --git a/src/PhpSpreadsheet/Style/ConditionalFormatting/Wizard/WizardAbstract.php b/src/PhpSpreadsheet/Style/ConditionalFormatting/Wizard/WizardAbstract.php
index 1af0504a6..e747cef4c 100644
--- a/src/PhpSpreadsheet/Style/ConditionalFormatting/Wizard/WizardAbstract.php
+++ b/src/PhpSpreadsheet/Style/ConditionalFormatting/Wizard/WizardAbstract.php
@@ -19,10 +19,7 @@ abstract class WizardAbstract
      */
     protected $expression;
 
-    /**
-     * @var string
-     */
-    protected $cellRange;
+    protected string $cellRange;
 
     /**
      * @var string
diff --git a/src/PhpSpreadsheet/Theme.php b/src/PhpSpreadsheet/Theme.php
index ab101f01e..ac4dbe560 100644
--- a/src/PhpSpreadsheet/Theme.php
+++ b/src/PhpSpreadsheet/Theme.php
@@ -4,11 +4,9 @@ namespace PhpOffice\PhpSpreadsheet;
 
 class Theme
 {
-    /** @var string */
-    private $themeColorName = 'Office';
+    private string $themeColorName = 'Office';
 
-    /** @var string */
-    private $themeFontName = 'Office';
+    private string $themeFontName = 'Office';
 
     public const COLOR_SCHEME_2013_PLUS_NAME = 'Office 2013+';
     public const COLOR_SCHEME_2013_PLUS = [
@@ -45,23 +43,17 @@ class Theme
     /** @var string[] */
     private $themeColors = self::COLOR_SCHEME_2007_2010;
 
-    /** @var string */
-    private $majorFontLatin = 'Cambria';
+    private string $majorFontLatin = 'Cambria';
 
-    /** @var string */
-    private $majorFontEastAsian = '';
+    private string $majorFontEastAsian = '';
 
-    /** @var string */
-    private $majorFontComplexScript = '';
+    private string $majorFontComplexScript = '';
 
-    /** @var string */
-    private $minorFontLatin = 'Calibri';
+    private string $minorFontLatin = 'Calibri';
 
-    /** @var string */
-    private $minorFontEastAsian = '';
+    private string $minorFontEastAsian = '';
 
-    /** @var string */
-    private $minorFontComplexScript = '';
+    private string $minorFontComplexScript = '';
 
     /**
      * Map of Major (header) fonts to write.
diff --git a/src/PhpSpreadsheet/Worksheet/BaseDrawing.php b/src/PhpSpreadsheet/Worksheet/BaseDrawing.php
index 06c4511fe..962c45a20 100644
--- a/src/PhpSpreadsheet/Worksheet/BaseDrawing.php
+++ b/src/PhpSpreadsheet/Worksheet/BaseDrawing.php
@@ -20,10 +20,8 @@ class BaseDrawing implements IComparable
 
     /**
      * The editAs attribute, used only with two cell anchor.
-     *
-     * @var string
      */
-    protected $editAs = '';
+    protected string $editAs = '';
 
     /**
      * Image counter.
@@ -39,31 +37,23 @@ class BaseDrawing implements IComparable
 
     /**
      * Name.
-     *
-     * @var string
      */
-    protected $name = '';
+    protected string $name = '';
 
     /**
      * Description.
-     *
-     * @var string
      */
-    protected $description = '';
+    protected string $description = '';
 
     /**
      * Worksheet.
-     *
-     * @var null|Worksheet
      */
-    protected $worksheet;
+    protected ?\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $worksheet = null;
 
     /**
      * Coordinates.
-     *
-     * @var string
      */
-    protected $coordinates = 'A1';
+    protected string $coordinates = 'A1';
 
     /**
      * Offset X.
@@ -81,10 +71,8 @@ class BaseDrawing implements IComparable
 
     /**
      * Coordinates2.
-     *
-     * @var string
      */
-    protected $coordinates2 = '';
+    protected string $coordinates2 = '';
 
     /**
      * Offset X2.
@@ -144,10 +132,8 @@ class BaseDrawing implements IComparable
 
     /**
      * Shadow.
-     *
-     * @var Drawing\Shadow
      */
-    protected $shadow;
+    protected \PhpOffice\PhpSpreadsheet\Worksheet\Drawing\Shadow $shadow;
 
     /**
      * Image hyperlink.
diff --git a/src/PhpSpreadsheet/Worksheet/Column.php b/src/PhpSpreadsheet/Worksheet/Column.php
index 077ba5da9..d2bbffb3a 100644
--- a/src/PhpSpreadsheet/Worksheet/Column.php
+++ b/src/PhpSpreadsheet/Worksheet/Column.php
@@ -4,19 +4,12 @@ namespace PhpOffice\PhpSpreadsheet\Worksheet;
 
 class Column
 {
-    /**
-     * \PhpOffice\PhpSpreadsheet\Worksheet\Worksheet.
-     *
-     * @var Worksheet
-     */
-    private $worksheet;
+    private ?Worksheet $worksheet;
 
     /**
      * Column index.
-     *
-     * @var string
      */
-    private $columnIndex;
+    private string $columnIndex;
 
     /**
      * Create a new column.
@@ -35,7 +28,6 @@ class Column
      */
     public function __destruct()
     {
-        // @phpstan-ignore-next-line
         $this->worksheet = null;
     }
 
@@ -55,7 +47,7 @@ class Column
      */
     public function getCellIterator($startRow = 1, $endRow = null): ColumnCellIterator
     {
-        return new ColumnCellIterator($this->worksheet, $this->columnIndex, $startRow, $endRow);
+        return new ColumnCellIterator($this->getWorksheet(), $this->columnIndex, $startRow, $endRow);
     }
 
     /**
@@ -116,6 +108,7 @@ class Column
      */
     public function getWorksheet(): Worksheet
     {
+        // @phpstan-ignore-next-line
         return $this->worksheet;
     }
 }
diff --git a/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php b/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
index b75d7a036..ba9312b49 100644
--- a/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
@@ -13,10 +13,8 @@ class ColumnCellIterator extends CellIterator
 {
     /**
      * Current iterator position.
-     *
-     * @var int
      */
-    private $currentRow;
+    private int $currentRow;
 
     /**
      * Column index.
diff --git a/src/PhpSpreadsheet/Worksheet/ColumnDimension.php b/src/PhpSpreadsheet/Worksheet/ColumnDimension.php
index 3c0ee2e4e..07f741342 100644
--- a/src/PhpSpreadsheet/Worksheet/ColumnDimension.php
+++ b/src/PhpSpreadsheet/Worksheet/ColumnDimension.php
@@ -9,10 +9,8 @@ class ColumnDimension extends Dimension
 {
     /**
      * Column index.
-     *
-     * @var ?string
      */
-    private $columnIndex;
+    private ?string $columnIndex;
 
     /**
      * Column width.
diff --git a/src/PhpSpreadsheet/Worksheet/Dimension.php b/src/PhpSpreadsheet/Worksheet/Dimension.php
index 7f144063b..8549b1695 100644
--- a/src/PhpSpreadsheet/Worksheet/Dimension.php
+++ b/src/PhpSpreadsheet/Worksheet/Dimension.php
@@ -29,10 +29,8 @@ abstract class Dimension
 
     /**
      * Index to cellXf. Null value means row has no explicit cellXf format.
-     *
-     * @var null|int
      */
-    private $xfIndex;
+    private ?int $xfIndex;
 
     /**
      * Create a new Dimension.
diff --git a/src/PhpSpreadsheet/Worksheet/PageBreak.php b/src/PhpSpreadsheet/Worksheet/PageBreak.php
index 2a0da4020..5099d8be0 100644
--- a/src/PhpSpreadsheet/Worksheet/PageBreak.php
+++ b/src/PhpSpreadsheet/Worksheet/PageBreak.php
@@ -10,8 +10,7 @@ class PageBreak
 {
     private int $breakType;
 
-    /** @var string */
-    private $coordinate;
+    private string $coordinate;
 
     private int $maxColOrRow;
 
diff --git a/src/PhpSpreadsheet/Worksheet/Protection.php b/src/PhpSpreadsheet/Worksheet/Protection.php
index 57d79addf..958a18dc6 100644
--- a/src/PhpSpreadsheet/Worksheet/Protection.php
+++ b/src/PhpSpreadsheet/Worksheet/Protection.php
@@ -19,115 +19,83 @@ class Protection
 
     /**
      * Autofilters are locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $autoFilter;
+    private ?bool $autoFilter = null;
 
     /**
      * Deleting columns is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $deleteColumns;
+    private ?bool $deleteColumns = null;
 
     /**
      * Deleting rows is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $deleteRows;
+    private ?bool $deleteRows = null;
 
     /**
      * Formatting cells is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $formatCells;
+    private ?bool $formatCells = null;
 
     /**
      * Formatting columns is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $formatColumns;
+    private ?bool $formatColumns = null;
 
     /**
      * Formatting rows is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $formatRows;
+    private ?bool $formatRows = null;
 
     /**
      * Inserting columns is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $insertColumns;
+    private ?bool $insertColumns = null;
 
     /**
      * Inserting hyperlinks is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $insertHyperlinks;
+    private ?bool $insertHyperlinks = null;
 
     /**
      * Inserting rows is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $insertRows;
+    private ?bool $insertRows = null;
 
     /**
      * Objects are locked when sheet is protected, default false.
-     *
-     * @var ?bool
      */
-    private $objects;
+    private ?bool $objects = null;
 
     /**
      * Pivot tables are locked when the sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $pivotTables;
+    private ?bool $pivotTables = null;
 
     /**
      * Scenarios are locked when sheet is protected, default false.
-     *
-     * @var ?bool
      */
-    private $scenarios;
+    private ?bool $scenarios = null;
 
     /**
      * Selection of locked cells is locked when sheet is protected, default false.
-     *
-     * @var ?bool
      */
-    private $selectLockedCells;
+    private ?bool $selectLockedCells = null;
 
     /**
      * Selection of unlocked cells is locked when sheet is protected, default false.
-     *
-     * @var ?bool
      */
-    private $selectUnlockedCells;
+    private ?bool $selectUnlockedCells = null;
 
     /**
      * Sheet is locked when sheet is protected, default false.
-     *
-     * @var ?bool
      */
-    private $sheet;
+    private ?bool $sheet = null;
 
     /**
      * Sorting is locked when sheet is protected, default true.
-     *
-     * @var ?bool
      */
-    private $sort;
+    private ?bool $sort = null;
 
     /**
      * Hashed password.
@@ -138,17 +106,13 @@ class Protection
 
     /**
      * Algorithm name.
-     *
-     * @var string
      */
-    private $algorithm = '';
+    private string $algorithm = '';
 
     /**
      * Salt value.
-     *
-     * @var string
      */
-    private $salt = '';
+    private string $salt = '';
 
     /**
      * Spin count.
diff --git a/src/PhpSpreadsheet/Worksheet/Row.php b/src/PhpSpreadsheet/Worksheet/Row.php
index b5f08816b..4d8ad57e3 100644
--- a/src/PhpSpreadsheet/Worksheet/Row.php
+++ b/src/PhpSpreadsheet/Worksheet/Row.php
@@ -4,12 +4,7 @@ namespace PhpOffice\PhpSpreadsheet\Worksheet;
 
 class Row
 {
-    /**
-     * \PhpOffice\PhpSpreadsheet\Worksheet\Worksheet.
-     *
-     * @var Worksheet
-     */
-    private $worksheet;
+    private ?Worksheet $worksheet;
 
     /**
      * Row index.
@@ -35,7 +30,7 @@ class Row
      */
     public function __destruct()
     {
-        $this->worksheet = null; // @phpstan-ignore-line
+        $this->worksheet = null;
     }
 
     /**
@@ -54,7 +49,7 @@ class Row
      */
     public function getCellIterator($startColumn = 'A', $endColumn = null): RowCellIterator
     {
-        return new RowCellIterator($this->worksheet, $this->rowIndex, $startColumn, $endColumn);
+        return new RowCellIterator($this->getWorksheet(), $this->rowIndex, $startColumn, $endColumn);
     }
 
     /**
@@ -115,6 +110,7 @@ class Row
      */
     public function getWorksheet(): Worksheet
     {
+        // @phpstan-ignore-next-line
         return $this->worksheet;
     }
 }
diff --git a/src/PhpSpreadsheet/Worksheet/RowCellIterator.php b/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
index e1563c33c..4174fd223 100644
--- a/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
@@ -13,10 +13,8 @@ class RowCellIterator extends CellIterator
 {
     /**
      * Current iterator position.
-     *
-     * @var int
      */
-    private $currentColumnIndex;
+    private int $currentColumnIndex;
 
     /**
      * Row index.
diff --git a/src/PhpSpreadsheet/Worksheet/RowDimension.php b/src/PhpSpreadsheet/Worksheet/RowDimension.php
index da839483b..b3c213a96 100644
--- a/src/PhpSpreadsheet/Worksheet/RowDimension.php
+++ b/src/PhpSpreadsheet/Worksheet/RowDimension.php
@@ -8,10 +8,8 @@ class RowDimension extends Dimension
 {
     /**
      * Row index.
-     *
-     * @var ?int
      */
-    private $rowIndex;
+    private ?int $rowIndex;
 
     /**
      * Row height (in pt).
diff --git a/src/PhpSpreadsheet/Worksheet/Table.php b/src/PhpSpreadsheet/Worksheet/Table.php
index 7de64d953..433081056 100644
--- a/src/PhpSpreadsheet/Worksheet/Table.php
+++ b/src/PhpSpreadsheet/Worksheet/Table.php
@@ -14,10 +14,8 @@ class Table
 {
     /**
      * Table Name.
-     *
-     * @var string
      */
-    private $name;
+    private string $name;
 
     /**
      * Show Header Row.
@@ -35,17 +33,13 @@ class Table
 
     /**
      * Table Range.
-     *
-     * @var string
      */
-    private $range = '';
+    private string $range = '';
 
     /**
      * Table Worksheet.
-     *
-     * @var null|Worksheet
      */
-    private $workSheet;
+    private ?\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet $workSheet = null;
 
     /**
      * Table allow filter.
@@ -166,7 +160,7 @@ class Table
 
     private function updateStructuredReferences(string $name): void
     {
-        if ($this->workSheet === null || $this->name === null || $this->name === '') {
+        if (!$this->workSheet || !$this->name) {
             return;
         }
 
diff --git a/src/PhpSpreadsheet/Worksheet/Table/Column.php b/src/PhpSpreadsheet/Worksheet/Table/Column.php
index 62b6765ab..c448a7434 100644
--- a/src/PhpSpreadsheet/Worksheet/Table/Column.php
+++ b/src/PhpSpreadsheet/Worksheet/Table/Column.php
@@ -12,10 +12,8 @@ class Column
 {
     /**
      * Table Column Index.
-     *
-     * @var string
      */
-    private $columnIndex = '';
+    private string $columnIndex = '';
 
     /**
      * Show Filter Button.
@@ -26,31 +24,23 @@ class Column
 
     /**
      * Total Row Label.
-     *
-     * @var string
      */
-    private $totalsRowLabel;
+    private ?string $totalsRowLabel = null;
 
     /**
      * Total Row Function.
-     *
-     * @var string
      */
-    private $totalsRowFunction;
+    private ?string $totalsRowFunction = null;
 
     /**
      * Total Row Formula.
-     *
-     * @var string
      */
-    private $totalsRowFormula;
+    private ?string $totalsRowFormula = null;
 
     /**
      * Column Formula.
-     *
-     * @var string
      */
-    private $columnFormula;
+    private ?string $columnFormula = null;
 
     /**
      * Table.
diff --git a/src/PhpSpreadsheet/Worksheet/Table/TableStyle.php b/src/PhpSpreadsheet/Worksheet/Table/TableStyle.php
index 54c378509..3587e82a2 100644
--- a/src/PhpSpreadsheet/Worksheet/Table/TableStyle.php
+++ b/src/PhpSpreadsheet/Worksheet/Table/TableStyle.php
@@ -103,10 +103,8 @@ class TableStyle
 
     /**
      * Table.
-     *
-     * @var null|Table
      */
-    private $table;
+    private ?\PhpOffice\PhpSpreadsheet\Worksheet\Table $table = null;
 
     /**
      * Create a new Table Style.
diff --git a/src/PhpSpreadsheet/Writer/Csv.php b/src/PhpSpreadsheet/Writer/Csv.php
index 823f8495e..5b332d4ae 100644
--- a/src/PhpSpreadsheet/Writer/Csv.php
+++ b/src/PhpSpreadsheet/Writer/Csv.php
@@ -14,17 +14,13 @@ class Csv extends BaseWriter
 
     /**
      * Delimiter.
-     *
-     * @var string
      */
-    private $delimiter = ',';
+    private string $delimiter = ',';
 
     /**
      * Enclosure.
-     *
-     * @var string
      */
-    private $enclosure = '"';
+    private string $enclosure = '"';
 
     /**
      * Line ending.
@@ -64,10 +60,8 @@ class Csv extends BaseWriter
 
     /**
      * Output encoding.
-     *
-     * @var string
      */
-    private $outputEncoding = '';
+    private string $outputEncoding = '';
 
     /**
      * Create a new CSV.
diff --git a/src/PhpSpreadsheet/Writer/Pdf.php b/src/PhpSpreadsheet/Writer/Pdf.php
index e2cce9ed9..e74bb8f38 100644
--- a/src/PhpSpreadsheet/Writer/Pdf.php
+++ b/src/PhpSpreadsheet/Writer/Pdf.php
@@ -23,10 +23,8 @@ abstract class Pdf extends Html
 
     /**
      * Orientation (Over-ride).
-     *
-     * @var ?string
      */
-    protected $orientation;
+    protected ?string $orientation = null;
 
     /**
      * Paper size (Over-ride).
diff --git a/src/PhpSpreadsheet/Writer/Xls/ConditionalHelper.php b/src/PhpSpreadsheet/Writer/Xls/ConditionalHelper.php
index a80c325b1..a64e2fa74 100644
--- a/src/PhpSpreadsheet/Writer/Xls/ConditionalHelper.php
+++ b/src/PhpSpreadsheet/Writer/Xls/ConditionalHelper.php
@@ -22,15 +22,9 @@ class ConditionalHelper
      */
     protected $cellRange;
 
-    /**
-     * @var null|string
-     */
-    protected $tokens;
+    protected ?string $tokens = null;
 
-    /**
-     * @var int
-     */
-    protected $size;
+    protected int $size;
 
     public function __construct(Parser $parser)
     {
diff --git a/tests/PhpSpreadsheetTests/Custom/ComplexAssert.php b/tests/PhpSpreadsheetTests/Custom/ComplexAssert.php
index e7df5a667..73c98afe2 100644
--- a/tests/PhpSpreadsheetTests/Custom/ComplexAssert.php
+++ b/tests/PhpSpreadsheetTests/Custom/ComplexAssert.php
@@ -9,10 +9,7 @@ use PHPUnit\Framework\TestCase;
 
 class ComplexAssert extends TestCase
 {
-    /**
-     * @var string
-     */
-    private $errorMessage = '';
+    private string $errorMessage = '';
 
     /** @var float */
     private $delta = 0.0;