diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 859c6f0..0a8a947 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -1,6 +1,17 @@
 <?php
 
-$config = new Amp\CodeStyle\Config();
+$config = new class extends Amp\CodeStyle\Config {
+    public function getRules(): array
+    {
+        return array_merge(
+            parent::getRules(),
+            [
+                'phpdoc_to_property_type' => true,
+                'phpdoc_to_param_type' => true,
+            ]
+        );
+    }  
+};
 $config->getFinder()
     ->in(__DIR__ . '/src')
     ->in(__DIR__ . '/tests');
diff --git a/composer.json b/composer.json
index 42f1aa1..53f63a9 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^9",
-        "amphp/php-cs-fixer-config": "dev-master"
+        "amphp/php-cs-fixer-config": "^2"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/FileId.php b/src/FileId.php
index cdc0af0..9fac9d3 100644
--- a/src/FileId.php
+++ b/src/FileId.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Decoded FileId class.
  *
@@ -32,78 +32,65 @@ class FileId
     /**
      * Bot API file ID version.
      *
-     * @var int
      */
-    private $_version = 4;
+    private int $version = 4;
 
     /**
      * Bot API file ID subversion.
      *
-     * @var int
      */
-    private $_subVersion = 47;
+    private int $subVersion = 47;
 
     /**
      * DC ID.
      *
-     * @var int
      */
-    private $_dcId = 0;
+    private int $dcId = 0;
 
     /**
      * File type.
      *
-     * @var int
      */
-    private $_type = 0;
+    private int $type = 0;
 
     /**
      * File reference.
      *
-     * @var string
      */
-    private $_fileReference = '';
+    private string $fileReference = '';
     /**
      * File URL for weblocation.
      *
-     * @var string
      */
-    private $_url = '';
-
+    private string $url = '';
 
     /**
      * File id.
      *
-     * @var int
      */
-    private $_id;
+    private int $id;
     /**
      * File access hash.
      *
-     * @var int
      */
-    private $_accessHash;
-
+    private int $accessHash;
 
     /**
      * Photo volume ID.
      *
-     * @var int
      */
-    private $_volumeId;
+    private int $volumeId;
     /**
      * Photo local ID.
      *
-     * @var int
      */
-    private $_localId;
+    private int $localId;
 
     /**
      * Photo size source.
      *
-     * @var PhotoSizeSource
      */
-    private $_photoSizeSource;
+    private PhotoSizeSource $photoSizeSource;
     /**
      * Basic constructor function.
      */
@@ -116,7 +103,6 @@ class FileId
      *
      * @param string $fileId File ID
      *
-     * @return self
      */
     public static function fromBotAPI(string $fileId): self
     {
@@ -182,11 +168,9 @@ class FileId
         return $result;
     }
 
-
     /**
      * Get bot API file ID.
      *
-     * @return string
      */
     public function getBotAPI(): string
     {
@@ -261,7 +245,6 @@ class FileId
     /**
      * Get unique file ID from file ID.
      *
-     * @return UniqueFileId
      */
     public function getUnique(): UniqueFileId
     {
@@ -270,7 +253,6 @@ class FileId
     /**
      * Get unique bot API file ID from file ID.
      *
-     * @return string
      */
     public function getUniqueBotAPI(): string
     {
@@ -279,7 +261,6 @@ class FileId
     /**
      * Get bot API file ID.
      *
-     * @return string
      */
     public function __toString(): string
     {
@@ -288,23 +269,21 @@ class FileId
     /**
      * Get bot API file ID version.
      *
-     * @return int
      */
     public function getVersion(): int
     {
-        return $this->_version;
+        return $this->version;
     }
 
     /**
      * Set bot API file ID version.
      *
-     * @param int $_version Bot API file ID version.
+     * @param int $version Bot API file ID version.
      *
-     * @return self
      */
-    public function setVersion(int $_version): self
+    public function setVersion(int $version): self
     {
-        $this->_version = $_version;
+        $this->version = $version;
 
         return $this;
     }
@@ -312,23 +291,21 @@ class FileId
     /**
      * Get bot API file ID subversion.
      *
-     * @return int
      */
     public function getSubVersion(): int
     {
-        return $this->_subVersion;
+        return $this->subVersion;
     }
 
     /**
      * Set bot API file ID subversion.
      *
-     * @param int $_subVersion Bot API file ID subversion.
+     * @param int $subVersion Bot API file ID subversion.
      *
-     * @return self
      */
-    public function setSubVersion(int $_subVersion): self
+    public function setSubVersion(int $subVersion): self
     {
-        $this->_subVersion = $_subVersion;
+        $this->subVersion = $subVersion;
 
         return $this;
     }
@@ -336,33 +313,30 @@ class FileId
     /**
      * Get file type.
      *
-     * @return int
      */
     public function getType(): int
     {
-        return $this->_type;
+        return $this->type;
     }
 
     /**
      * Get file type as string.
      *
-     * @return string
      */
     public function getTypeName(): string
     {
-        return TYPES[$this->_type];
+        return TYPES[$this->type];
     }
 
     /**
      * Set file type.
      *
-     * @param int $_type File type.
+     * @param int $type File type.
      *
-     * @return self
      */
-    public function setType(int $_type): self
+    public function setType(int $type): self
     {
-        $this->_type = $_type;
+        $this->type = $type;
 
         return $this;
     }
@@ -370,23 +344,21 @@ class FileId
     /**
      * Get file reference.
      *
-     * @return string
      */
     public function getFileReference(): string
     {
-        return $this->_fileReference;
+        return $this->fileReference;
     }
 
     /**
      * Set file reference.
      *
-     * @param string $_fileReference File reference.
+     * @param string $fileReference File reference.
      *
-     * @return self
      */
-    public function setFileReference(string $_fileReference): self
+    public function setFileReference(string $fileReference): self
     {
-        $this->_fileReference = $_fileReference;
+        $this->fileReference = $fileReference;
 
         return $this;
     }
@@ -398,17 +370,16 @@ class FileId
      */
     public function hasFileReference(): bool
     {
-        return !empty($this->_fileReference);
+        return !empty($this->fileReference);
     }
 
     /**
      * Get file URL for weblocation.
      *
-     * @return string
      */
     public function getUrl(): string
     {
-        return $this->_url;
+        return $this->url;
     }
 
     /**
@@ -418,19 +389,18 @@ class FileId
      */
     public function hasUrl(): bool
     {
-        return !empty($this->_url);
+        return !empty($this->url);
     }
 
     /**
      * Set file URL for weblocation.
      *
-     * @param string $_url File URL for weblocation.
+     * @param string $url File URL for weblocation.
      *
-     * @return self
      */
-    public function setUrl(string $_url): self
+    public function setUrl(string $url): self
     {
-        $this->_url = $_url;
+        $this->url = $url;
 
         return $this;
     }
@@ -442,19 +412,18 @@ class FileId
      */
     public function getId()
     {
-        return $this->_id;
+        return $this->id;
     }
 
     /**
      * Set file id.
      *
-     * @param int $_id File id.
+     * @param int $id File id.
      *
-     * @return self
      */
-    public function setId($_id): self
+    public function setId(int $id): self
     {
-        $this->_id = $_id;
+        $this->id = $id;
 
         return $this;
     }
@@ -462,11 +431,10 @@ class FileId
     /**
      * Check if has file id.
      *
-     * @return bool
      */
     public function hasId(): bool
     {
-        return isset($this->_id);
+        return isset($this->id);
     }
 
     /**
@@ -476,19 +444,18 @@ class FileId
      */
     public function getAccessHash()
     {
-        return $this->_accessHash;
+        return $this->accessHash;
     }
 
     /**
      * Set file access hash.
      *
-     * @param int $_accessHash File access hash.
+     * @param int $accessHash File access hash.
      *
-     * @return self
      */
-    public function setAccessHash($_accessHash): self
+    public function setAccessHash(int $accessHash): self
     {
-        $this->_accessHash = $_accessHash;
+        $this->accessHash = $accessHash;
 
         return $this;
     }
@@ -500,19 +467,18 @@ class FileId
      */
     public function getVolumeId()
     {
-        return $this->_volumeId;
+        return $this->volumeId;
     }
 
     /**
      * Set photo volume ID.
      *
-     * @param int $_volumeId Photo volume ID.
+     * @param int $volumeId Photo volume ID.
      *
-     * @return self
      */
-    public function setVolumeId($_volumeId): self
+    public function setVolumeId(int $volumeId): self
     {
-        $this->_volumeId = $_volumeId;
+        $this->volumeId = $volumeId;
 
         return $this;
     }
@@ -523,29 +489,27 @@ class FileId
      */
     public function hasVolumeId(): bool
     {
-        return isset($this->_volumeId);
+        return isset($this->volumeId);
     }
 
     /**
      * Get photo local ID.
      *
-     * @return int
      */
     public function getLocalId(): int
     {
-        return $this->_localId;
+        return $this->localId;
     }
 
     /**
      * Set photo local ID.
      *
-     * @param int $_localId Photo local ID.
+     * @param int $localId Photo local ID.
      *
-     * @return self
      */
-    public function setLocalId(int $_localId): self
+    public function setLocalId(int $localId): self
     {
-        $this->_localId = $_localId;
+        $this->localId = $localId;
 
         return $this;
     }
@@ -557,29 +521,27 @@ class FileId
      */
     public function hasLocalId(): bool
     {
-        return isset($this->_localId);
+        return isset($this->localId);
     }
 
     /**
      * Get photo size source.
      *
-     * @return PhotoSizeSource
      */
     public function getPhotoSizeSource(): PhotoSizeSource
     {
-        return $this->_photoSizeSource;
+        return $this->photoSizeSource;
     }
 
     /**
      * Set photo size source.
      *
-     * @param PhotoSizeSource $_photoSizeSource Photo size source.
+     * @param PhotoSizeSource $photoSizeSource Photo size source.
      *
-     * @return self
      */
-    public function setPhotoSizeSource(PhotoSizeSource $_photoSizeSource): self
+    public function setPhotoSizeSource(PhotoSizeSource $photoSizeSource): self
     {
-        $this->_photoSizeSource = $_photoSizeSource;
+        $this->photoSizeSource = $photoSizeSource;
 
         return $this;
     }
@@ -591,29 +553,27 @@ class FileId
      */
     public function hasPhotoSizeSource(): bool
     {
-        return isset($this->_photoSizeSource);
+        return isset($this->photoSizeSource);
     }
 
     /**
      * Get dC ID.
      *
-     * @return int
      */
     public function getDcId(): int
     {
-        return $this->_dcId;
+        return $this->dcId;
     }
 
     /**
      * Set dC ID.
      *
-     * @param int $_dcId DC ID.
+     * @param int $dcId DC ID.
      *
-     * @return self
      */
-    public function setDcId(int $_dcId): self
+    public function setDcId(int $dcId): self
     {
-        $this->_dcId = $_dcId;
+        $this->dcId = $dcId;
 
         return $this;
     }
diff --git a/src/PhotoSizeSource.php b/src/PhotoSizeSource.php
index f819dfd..2a12949 100644
--- a/src/PhotoSizeSource.php
+++ b/src/PhotoSizeSource.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Photosize source class.
  *
@@ -30,9 +30,8 @@ abstract class PhotoSizeSource
     /**
      * Source type.
      *
-     * @var int
      */
-    private $_type;
+    private int $type;
 
     /**
      * Set photosize source type.
@@ -41,7 +40,7 @@ abstract class PhotoSizeSource
      */
     public function __construct(int $type)
     {
-        $this->_type = $type;
+        $this->type = $type;
 
         return $this;
     }
@@ -65,6 +64,6 @@ abstract class PhotoSizeSource
      */
     public function getType(): int
     {
-        return $this->_type;
+        return $this->type;
     }
 }
diff --git a/src/PhotoSizeSource/PhotoSizeSourceDialogPhoto.php b/src/PhotoSizeSource/PhotoSizeSourceDialogPhoto.php
index 8bdfd90..97f78f5 100644
--- a/src/PhotoSizeSource/PhotoSizeSourceDialogPhoto.php
+++ b/src/PhotoSizeSource/PhotoSizeSourceDialogPhoto.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Photosize source class.
  *
@@ -33,15 +33,13 @@ class PhotoSizeSourceDialogPhoto extends PhotoSizeSource
     /**
      * ID of dialog.
      *
-     * @var int
      */
-    private $_dialogId;
+    private int $dialogId;
     /**
      * Access hash of dialog.
      *
-     * @var int
      */
-    private $_dialogAccessHash;
+    private int $dialogAccessHash;
 
     /**
      * Get dialog ID.
@@ -50,18 +48,17 @@ class PhotoSizeSourceDialogPhoto extends PhotoSizeSource
      */
     public function getDialogId()
     {
-        return $this->_dialogId;
+        return $this->dialogId;
     }
     /**
      * Set dialog ID.
      *
      * @param int $id Dialog ID
      *
-     * @return self
      */
-    public function setDialogId($id): self
+    public function setDialogId(int $id): self
     {
-        $this->_dialogId = $id;
+        $this->dialogId = $id;
         return $this;
     }
     /**
@@ -71,7 +68,7 @@ class PhotoSizeSourceDialogPhoto extends PhotoSizeSource
      */
     public function getDialogAccessHash()
     {
-        return $this->_dialogAccessHash;
+        return $this->dialogAccessHash;
     }
 
     /**
@@ -79,11 +76,10 @@ class PhotoSizeSourceDialogPhoto extends PhotoSizeSource
      *
      * @param int $dialogAccessHash Access hash of dialog
      *
-     * @return self
      */
-    public function setDialogAccessHash($dialogAccessHash): self
+    public function setDialogAccessHash(int $dialogAccessHash): self
     {
-        $this->_dialogAccessHash = $dialogAccessHash;
+        $this->dialogAccessHash = $dialogAccessHash;
 
         return $this;
     }
@@ -91,7 +87,6 @@ class PhotoSizeSourceDialogPhoto extends PhotoSizeSource
     /**
      * Get whether the big or small version of the photo is being used.
      *
-     * @return bool
      */
     public function isSmallDialogPhoto(): bool
     {
diff --git a/src/PhotoSizeSource/PhotoSizeSourceLegacy.php b/src/PhotoSizeSource/PhotoSizeSourceLegacy.php
index c23dd22..1a16c50 100644
--- a/src/PhotoSizeSource/PhotoSizeSourceLegacy.php
+++ b/src/PhotoSizeSource/PhotoSizeSourceLegacy.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Photosize source class.
  *
@@ -30,9 +30,8 @@ class PhotoSizeSourceLegacy extends PhotoSizeSource
     /**
      * Secret legacy ID.
      *
-     * @var int
      */
-    private $_secret;
+    private int $secret;
 
     /**
      * Get secret legacy ID.
@@ -41,19 +40,18 @@ class PhotoSizeSourceLegacy extends PhotoSizeSource
      */
     public function getSecret()
     {
-        return $this->_secret;
+        return $this->secret;
     }
 
     /**
      * Set secret legacy ID.
      *
-     * @param int $_secret Secret legacy ID
+     * @param int $secret Secret legacy ID
      *
-     * @return self
      */
-    public function setSecret($_secret): self
+    public function setSecret(int $secret): self
     {
-        $this->_secret = $_secret;
+        $this->secret = $secret;
 
         return $this;
     }
diff --git a/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnail.php b/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnail.php
index 5069b3d..af48b47 100644
--- a/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnail.php
+++ b/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnail.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Photosize source class.
  *
@@ -30,16 +30,13 @@ class PhotoSizeSourceStickersetThumbnail extends PhotoSizeSource
     /**
      * Stickerset ID.
      *
-     * @var int
      */
-    private $_stickerSetId;
+    private int $stickerSetId;
     /**
      * Stickerset access hash.
      *
-     * @var int
      */
-    private $_stickerSetAccessHash;
-
+    private int $stickerSetAccessHash;
 
     /**
      * Get stickerset ID.
@@ -48,19 +45,18 @@ class PhotoSizeSourceStickersetThumbnail extends PhotoSizeSource
      */
     public function getStickerSetId()
     {
-        return $this->_stickerSetId;
+        return $this->stickerSetId;
     }
 
     /**
      * Set stickerset ID.
      *
-     * @param int $_stickerSetId Stickerset ID
+     * @param int $stickerSetId Stickerset ID
      *
-     * @return self
      */
-    public function setStickerSetId($_stickerSetId): self
+    public function setStickerSetId(int $stickerSetId): self
     {
-        $this->_stickerSetId = $_stickerSetId;
+        $this->stickerSetId = $stickerSetId;
 
         return $this;
     }
@@ -72,19 +68,18 @@ class PhotoSizeSourceStickersetThumbnail extends PhotoSizeSource
      */
     public function getStickerSetAccessHash()
     {
-        return $this->_stickerSetAccessHash;
+        return $this->stickerSetAccessHash;
     }
 
     /**
      * Set stickerset access hash.
      *
-     * @param int $_stickerSetAccessHash Stickerset access hash
+     * @param int $stickerSetAccessHash Stickerset access hash
      *
-     * @return self
      */
-    public function setStickerSetAccessHash($_stickerSetAccessHash): self
+    public function setStickerSetAccessHash(int $stickerSetAccessHash): self
     {
-        $this->_stickerSetAccessHash = $_stickerSetAccessHash;
+        $this->stickerSetAccessHash = $stickerSetAccessHash;
 
         return $this;
     }
diff --git a/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnailVersion.php b/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnailVersion.php
index f230074..b06f02d 100644
--- a/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnailVersion.php
+++ b/src/PhotoSizeSource/PhotoSizeSourceStickersetThumbnailVersion.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Photosize source class.
  *
@@ -30,22 +30,18 @@ class PhotoSizeSourceStickersetThumbnailVersion extends PhotoSizeSource
     /**
      * Stickerset ID.
      *
-     * @var int
      */
-    private $_stickerSetId;
+    private int $stickerSetId;
     /**
      * Stickerset access hash.
      *
-     * @var int
      */
-    private $_stickerSetAccessHash;
+    private int $stickerSetAccessHash;
     /**
      * Stickerset version.
      *
-     * @var int
      */
-    private $_stickerSetVersion;
-
+    private int $stickerSetVersion;
 
     /**
      * Get stickerset ID.
@@ -54,19 +50,18 @@ class PhotoSizeSourceStickersetThumbnailVersion extends PhotoSizeSource
      */
     public function getStickerSetId()
     {
-        return $this->_stickerSetId;
+        return $this->stickerSetId;
     }
 
     /**
      * Set stickerset ID.
      *
-     * @param int $_stickerSetId Stickerset ID
+     * @param int $stickerSetId Stickerset ID
      *
-     * @return self
      */
-    public function setStickerSetId($_stickerSetId): self
+    public function setStickerSetId(int $stickerSetId): self
     {
-        $this->_stickerSetId = $_stickerSetId;
+        $this->stickerSetId = $stickerSetId;
 
         return $this;
     }
@@ -78,19 +73,18 @@ class PhotoSizeSourceStickersetThumbnailVersion extends PhotoSizeSource
      */
     public function getStickerSetAccessHash()
     {
-        return $this->_stickerSetAccessHash;
+        return $this->stickerSetAccessHash;
     }
 
     /**
      * Set stickerset access hash.
      *
-     * @param int $_stickerSetAccessHash Stickerset access hash
+     * @param int $stickerSetAccessHash Stickerset access hash
      *
-     * @return self
      */
-    public function setStickerSetAccessHash($_stickerSetAccessHash): self
+    public function setStickerSetAccessHash(int $stickerSetAccessHash): self
     {
-        $this->_stickerSetAccessHash = $_stickerSetAccessHash;
+        $this->stickerSetAccessHash = $stickerSetAccessHash;
 
         return $this;
     }
@@ -98,23 +92,21 @@ class PhotoSizeSourceStickersetThumbnailVersion extends PhotoSizeSource
     /**
      * Get stickerset version.
      *
-     * @return int
      */
     public function getStickerSetVersion(): int
     {
-        return $this->_stickerSetVersion;
+        return $this->stickerSetVersion;
     }
 
     /**
      * Set stickerset version.
      *
-     * @param int $_stickerSetVersion Stickerset version.
+     * @param int $stickerSetVersion Stickerset version.
      *
-     * @return self
      */
-    public function setStickerSetVersion(int $_stickerSetVersion): self
+    public function setStickerSetVersion(int $stickerSetVersion): self
     {
-        $this->_stickerSetVersion = $_stickerSetVersion;
+        $this->stickerSetVersion = $stickerSetVersion;
 
         return $this;
     }
diff --git a/src/PhotoSizeSource/PhotoSizeSourceThumbnail.php b/src/PhotoSizeSource/PhotoSizeSourceThumbnail.php
index 75453aa..e81b2b0 100644
--- a/src/PhotoSizeSource/PhotoSizeSourceThumbnail.php
+++ b/src/PhotoSizeSource/PhotoSizeSourceThumbnail.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Photosize source class.
  *
@@ -30,45 +30,40 @@ class PhotoSizeSourceThumbnail extends PhotoSizeSource
     /**
      * File type of original file.
      *
-     * @var int
      */
-    private $_thumbFileType;
+    private int $thumbFileType;
     /**
      * Thumbnail size.
      *
-     * @var string
      */
-    private $_thumbType;
+    private string $thumbType;
 
     /**
      * Get file type of original file.
      *
-     * @return int
      */
     public function getThumbFileType(): int
     {
-        return $this->_thumbFileType;
+        return $this->thumbFileType;
     }
     /**
      * Get file type of original file as string.
      *
-     * @return string
      */
     public function getThumbFileTypeString(): string
     {
-        return TYPES[$this->_thumbFileType];
+        return TYPES[$this->thumbFileType];
     }
 
     /**
      * Set file type of original file.
      *
-     * @param int $_thumbFileType File type of original file
+     * @param int $thumbFileType File type of original file
      *
-     * @return self
      */
-    public function setThumbFileType(int $_thumbFileType): self
+    public function setThumbFileType(int $thumbFileType): self
     {
-        $this->_thumbFileType = $_thumbFileType;
+        $this->thumbFileType = $thumbFileType;
 
         return $this;
     }
@@ -76,23 +71,21 @@ class PhotoSizeSourceThumbnail extends PhotoSizeSource
     /**
      * Get thumbnail size.
      *
-     * @return string
      */
     public function getThumbType(): string
     {
-        return $this->_thumbType;
+        return $this->thumbType;
     }
 
     /**
      * Set thumbnail size.
      *
-     * @param string $_thumbType Thumbnail size
+     * @param string $thumbType Thumbnail size
      *
-     * @return self
      */
-    public function setThumbType(string $_thumbType): self
+    public function setThumbType(string $thumbType): self
     {
-        $this->_thumbType = $_thumbType;
+        $this->thumbType = $thumbType;
 
         return $this;
     }
diff --git a/src/UniqueFileId.php b/src/UniqueFileId.php
index 3fdc8ad..979cf77 100644
--- a/src/UniqueFileId.php
+++ b/src/UniqueFileId.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Decoded UniqueFileId class.
  *
@@ -30,51 +30,43 @@ class UniqueFileId
     /**
      * File type.
      *
-     * @var int
      */
-    private $_type = NONE;
+    private int $type = NONE;
     /**
      * File ID.
      *
-     * @var int
      */
-    private $_id;
+    private int $id;
     /**
      * Photo volume ID.
      *
-     * @var int
      */
-    private $_volumeId;
+    private int $volumeId;
     /**
      * Photo local ID.
      *
-     * @var int
      */
-    private $_localId;
+    private int $localId;
     /**
      * Photo subtype.
      *
-     * @var int
      */
-    private $_subType;
+    private int $subType;
     /**
      * Sticker set ID.
      *
-     * @var int
      */
-    private $_stickerSetId;
+    private int $stickerSetId;
     /**
      * Sticker set version.
      *
-     * @var int
      */
-    private $_stickerSetVersion;
+    private int $stickerSetVersion;
     /**
      * Weblocation URL.
      *
-     * @var string
      */
-    private $_url;
+    private string $url;
     /**
      * Basic constructor function.
      */
@@ -85,7 +77,6 @@ class UniqueFileId
     /**
      * Get unique bot API file ID.
      *
-     * @return string
      */
     public function __toString(): string
     {
@@ -95,7 +86,6 @@ class UniqueFileId
     /**
      * Get unique bot API file ID.
      *
-     * @return string
      */
     public function getUniqueBotAPI(): string
     {
@@ -126,7 +116,6 @@ class UniqueFileId
      *
      * @param string $fileId Bot API file ID
      *
-     * @return self
      */
     public static function fromUniqueBotAPI(string $fileId): self
     {
@@ -159,7 +148,6 @@ class UniqueFileId
      *
      * @param string $fileId Full bot API file ID
      *
-     * @return self
      */
     public static function fromBotAPI(string $fileId): self
     {
@@ -171,7 +159,6 @@ class UniqueFileId
      *
      * @param FileId $fileId Full file ID
      *
-     * @return self
      */
     public static function fromFileId(FileId $fileId): self
     {
@@ -217,33 +204,30 @@ class UniqueFileId
     /**
      * Get unique file type as string.
      *
-     * @return string
      */
     public function getTypeName(): string
     {
-        return UNIQUE_TYPES[$this->_type];
+        return UNIQUE_TYPES[$this->type];
     }
 
     /**
      * Get unique file type.
      *
-     * @return int
      */
     public function getType(): int
     {
-        return $this->_type;
+        return $this->type;
     }
 
     /**
      * Set file type.
      *
-     * @param int $_type File type.
+     * @param int $type File type.
      *
-     * @return self
      */
-    public function setType(int $_type): self
+    public function setType(int $type): self
     {
-        $this->_type = $_type;
+        $this->type = $type;
 
         return $this;
     }
@@ -255,19 +239,18 @@ class UniqueFileId
      */
     public function getId()
     {
-        return $this->_id;
+        return $this->id;
     }
 
     /**
      * Set file ID.
      *
-     * @param int $_id File ID.
+     * @param int $id File ID.
      *
-     * @return self
      */
-    public function setId($_id): self
+    public function setId(int $id): self
     {
-        $this->_id = $_id;
+        $this->id = $id;
 
         return $this;
     }
@@ -279,10 +262,9 @@ class UniqueFileId
      */
     public function hasId(): bool
     {
-        return isset($this->_id);
+        return isset($this->id);
     }
 
-
     /**
      * Get photo volume ID.
      *
@@ -290,19 +272,18 @@ class UniqueFileId
      */
     public function getVolumeId()
     {
-        return $this->_volumeId;
+        return $this->volumeId;
     }
 
     /**
      * Set photo volume ID.
      *
-     * @param int $_volumeId Photo volume ID.
+     * @param int $volumeId Photo volume ID.
      *
-     * @return self
      */
-    public function setVolumeId($_volumeId): self
+    public function setVolumeId(int $volumeId): self
     {
-        $this->_volumeId = $_volumeId;
+        $this->volumeId = $volumeId;
 
         return $this;
     }
@@ -313,29 +294,27 @@ class UniqueFileId
      */
     public function hasVolumeId(): bool
     {
-        return isset($this->_volumeId);
+        return isset($this->volumeId);
     }
 
     /**
      * Get photo local ID.
      *
-     * @return int
      */
     public function getLocalId(): int
     {
-        return $this->_localId;
+        return $this->localId;
     }
 
     /**
      * Set photo local ID.
      *
-     * @param int $_localId Photo local ID.
+     * @param int $localId Photo local ID.
      *
-     * @return self
      */
-    public function setLocalId(int $_localId): self
+    public function setLocalId(int $localId): self
     {
-        $this->_localId = $_localId;
+        $this->localId = $localId;
 
         return $this;
     }
@@ -347,30 +326,27 @@ class UniqueFileId
      */
     public function hasLocalId(): bool
     {
-        return isset($this->_localId);
+        return isset($this->localId);
     }
 
-
     /**
      * Get weblocation URL.
      *
-     * @return string
      */
     public function getUrl(): string
     {
-        return $this->_url;
+        return $this->url;
     }
 
     /**
      * Set weblocation URL.
      *
-     * @param string $_url Weblocation URL
+     * @param string $url Weblocation URL
      *
-     * @return self
      */
-    public function setUrl(string $_url): self
+    public function setUrl(string $url): self
     {
-        $this->_url = $_url;
+        $this->url = $url;
 
         return $this;
     }
@@ -382,39 +358,36 @@ class UniqueFileId
      */
     public function hasUrl(): bool
     {
-        return isset($this->_url);
+        return isset($this->url);
     }
 
     /**
      * Get photo subtype.
      *
-     * @return int
      */
     public function getSubType(): int
     {
-        return $this->_subType;
+        return $this->subType;
     }
 
     /**
      * Has photo subtype?
      *
-     * @return bool
      */
     public function hasSubType(): bool
     {
-        return isset($this->_subType);
+        return isset($this->subType);
     }
 
     /**
      * Set photo subtype.
      *
-     * @param int $_subType Photo subtype
+     * @param int $subType Photo subtype
      *
-     * @return self
      */
-    public function setSubType(int $_subType): self
+    public function setSubType(int $subType): self
     {
-        $this->_subType = $_subType;
+        $this->subType = $subType;
 
         return $this;
     }
@@ -426,30 +399,27 @@ class UniqueFileId
      */
     public function getStickerSetId()
     {
-        return $this->_stickerSetId;
+        return $this->stickerSetId;
     }
 
-
     /**
      * Has sticker set ID?
      *
-     * @return bool
      */
     public function hasStickerSetId(): bool
     {
-        return isset($this->_stickerSetId);
+        return isset($this->stickerSetId);
     }
 
     /**
      * Set sticker set ID.
      *
-     * @param int $_stickerSetId Sticker set ID
+     * @param int $stickerSetId Sticker set ID
      *
-     * @return self
      */
-    public function setStickerSetId($_stickerSetId): self
+    public function setStickerSetId(int $stickerSetId): self
     {
-        $this->_stickerSetId = $_stickerSetId;
+        $this->stickerSetId = $stickerSetId;
 
         return $this;
     }
@@ -457,33 +427,30 @@ class UniqueFileId
     /**
      * Get sticker set version.
      *
-     * @return int
      */
     public function getStickerSetVersion(): int
     {
-        return $this->_stickerSetVersion;
+        return $this->stickerSetVersion;
     }
 
     /**
      * Has sticker set version.
      *
-     * @return bool
      */
     public function hasStickerSetVersion(): bool
     {
-        return isset($this->_stickerSetVersion);
+        return isset($this->stickerSetVersion);
     }
 
     /**
      * Set sticker set version.
      *
-     * @param int $_stickerSetVersion Sticker set version
+     * @param int $stickerSetVersion Sticker set version
      *
-     * @return self
      */
-    public function setStickerSetVersion(int $_stickerSetVersion): self
+    public function setStickerSetVersion(int $stickerSetVersion): self
     {
-        $this->_stickerSetVersion = $_stickerSetVersion;
+        $this->stickerSetVersion = $stickerSetVersion;
 
         return $this;
     }
diff --git a/src/type.php b/src/type.php
index f318292..9d48d15 100644
--- a/src/type.php
+++ b/src/type.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Type enum + helper functions.
  *
@@ -226,11 +226,9 @@ function unpackLong(string $field)
 /**
  * Pack string long.
  *
- * @param string|int $field
  *
- * @return string
  */
-function packLongBig($field): string
+function packLongBig(string|int $field): string
 {
     if (PHP_INT_SIZE === 8) {
         /** @psalm-suppress InvalidGlobal */
@@ -272,9 +270,8 @@ function fixLong(array &$params, string $field)
  *
  * @param string|int|int[] $fields Fields to encode
  *
- * @return string
  */
-function packLong($fields): string
+function packLong(string|int|array $fields): string
 {
     if (\is_string($fields)) { // Already encoded, we hope
         return $fields;
@@ -292,7 +289,6 @@ function packLong($fields): string
  *
  * @internal
  *
- * @return string
  */
 function base64urlDecode(string $data): string
 {
@@ -306,7 +302,6 @@ function base64urlDecode(string $data): string
  *
  * @internal
  *
- * @return string
  */
 function base64urlEncode(string $data): string
 {
@@ -320,7 +315,6 @@ function base64urlEncode(string $data): string
  *
  * @internal
  *
- * @return string
  */
 function rleDecode(string $string): string
 {
@@ -348,7 +342,6 @@ function rleDecode(string $string): string
  *
  * @internal
  *
- * @return string
  */
 function rleEncode(string $string): string
 {
@@ -374,7 +367,6 @@ function rleEncode(string $string): string
     return $new;
 }
 
-
 /**
  * Positive modulo
  * Works just like the % (modulus) operator, only returns always a postive number.
@@ -400,9 +392,8 @@ function posmod(int $a, int $b): int
  *
  * @internal
  *
- * @return string
  */
-function readTLString($stream): string
+function readTLString(mixed $stream): string
 {
     $l = \ord(\stream_get_contents($stream, 1));
     if ($l > 254) {
@@ -430,7 +421,6 @@ function readTLString($stream): string
  *
  * @param string $string String
  *
- * @return string
  */
 function packTLString(string $string): string
 {
@@ -458,7 +448,6 @@ function packTLString(string $string): string
  *
  * @internal
  *
- * @return array
  */
 function internalDecode(string $fileId): array
 {
@@ -583,14 +572,12 @@ function internalDecode(string $fileId): array
  *
  * @internal
  *
- * @return array
  */
 function internalDecodeUnique(string $fileId): array
 {
     $orig = $fileId;
     $fileId = rleDecode(base64urlDecode($fileId));
 
-
     $result = \unpack('VtypeId', $fileId);
     if (!isset(UNIQUE_TYPES[$result['typeId']])) {
         throw new \InvalidArgumentException("Invalid file type provided: {$result['typeId']}");
diff --git a/tests/IntegrationTest.php b/tests/IntegrationTest.php
index 2f8a587..3fa31cd 100644
--- a/tests/IntegrationTest.php
+++ b/tests/IntegrationTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace danog\Decoder\Test;
 
@@ -13,7 +13,6 @@ use const danog\Decoder\TYPES_IDS;
 class IntegrationTest extends TestCase
 {
     /**
-     * @param string $fileId File ID
      * @param string $type   Expected type
      *
      * @dataProvider provideFileIdsAndType