diff --git a/Cartfile b/Cartfile
index cb68a79..6887339 100644
--- a/Cartfile
+++ b/Cartfile
@@ -1 +1 @@
-github "SDWebImage/SDWebImage" ~> 5.5
\ No newline at end of file
+github "SDWebImage/SDWebImage" ~> 5.6
\ No newline at end of file
diff --git a/Cartfile.resolved b/Cartfile.resolved
index 0e510c6..417dabe 100644
--- a/Cartfile.resolved
+++ b/Cartfile.resolved
@@ -1 +1 @@
-github "SDWebImage/SDWebImage" "5.5.2"
+github "SDWebImage/SDWebImage" "5.6.0"
diff --git a/Package.swift b/Package.swift
index d92cd22..8c97951 100644
--- a/Package.swift
+++ b/Package.swift
@@ -17,7 +17,7 @@ let package = Package(
     dependencies: [
         // Dependencies declare other packages that this package depends on.
         // .package(url: /* package url */, from: "1.0.0"),
-        .package(url: "https://github.com/SDWebImage/SDWebImage.git", from: "5.5.0")
+        .package(url: "https://github.com/SDWebImage/SDWebImage.git", from: "5.6.0")
     ],
     targets: [
         // Targets are the basic building blocks of a package. A target can define a module or a test suite.
diff --git a/SDWebImagePDFCoder.podspec b/SDWebImagePDFCoder.podspec
index 35fab1d..4a16c7b 100644
--- a/SDWebImagePDFCoder.podspec
+++ b/SDWebImagePDFCoder.podspec
@@ -39,5 +39,5 @@ SDWebImageSVGCoder is a SVG coder plugin for SDWebImage framework, which provide
     'DERIVE_MACCATALYST_PRODUCT_BUNDLE_IDENTIFIER' => 'NO'
   }
   
-  s.dependency 'SDWebImage', '~> 5.5'
+  s.dependency 'SDWebImage', '~> 5.6'
 end
diff --git a/SDWebImagePDFCoder/Classes/SDImagePDFCoder.h b/SDWebImagePDFCoder/Classes/SDImagePDFCoder.h
index a0949b4..a4854c8 100644
--- a/SDWebImagePDFCoder/Classes/SDImagePDFCoder.h
+++ b/SDWebImagePDFCoder/Classes/SDImagePDFCoder.h
@@ -13,8 +13,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-static const SDImageFormat SDImageFormatPDF = 13;
-
 /***
  SDImagePDFCoder is a PDF image coder, which use the built-in UIKit/AppKit method to decode PDF images. And it will use the Core Graphics to draw PDF images when needed (For example, current firmware does not support built-in rendering). This class does not use PDFKit framwork because we focus on PDF vector images but not document pages rendering.