diff --git a/Package.swift b/Package.swift
index b49a607..b0e4b24 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:4.1
+// swift-tools-version:5.1
 import PackageDescription
 
 var package = Package(
diff --git a/Sources/WKCodable/WKBEncoder.swift b/Sources/WKCodable/WKBEncoder.swift
index 0cd7ade..92f377e 100644
--- a/Sources/WKCodable/WKBEncoder.swift
+++ b/Sources/WKCodable/WKBEncoder.swift
@@ -14,7 +14,7 @@ public extension WKBEncoder {
     }
 }
 
-public extension WKBEncoder {
+extension WKBEncoder {
     
     // MARK: - Public
     
diff --git a/Sources/WKCodable/WKTDecoder.swift b/Sources/WKCodable/WKTDecoder.swift
index b16b91d..6cd660c 100644
--- a/Sources/WKCodable/WKTDecoder.swift
+++ b/Sources/WKCodable/WKTDecoder.swift
@@ -13,7 +13,7 @@ public extension WKTDecoder {
     }
 }
 
-public extension WKTDecoder {
+extension WKTDecoder {
     
     // MARK: - Public
 
diff --git a/Sources/WKCodable/WKTEncoder.swift b/Sources/WKCodable/WKTEncoder.swift
index 48c6ed3..a2da1bf 100644
--- a/Sources/WKCodable/WKTEncoder.swift
+++ b/Sources/WKCodable/WKTEncoder.swift
@@ -5,7 +5,7 @@ public class WKTEncoder {
     private var result: String = ""
 }
 
-public extension WKTEncoder {
+extension WKTEncoder {
     
     // MARK: - Public