diff --git a/.swift-version b/.swift-version
index bf77d54..819e07a 100644
--- a/.swift-version
+++ b/.swift-version
@@ -1 +1 @@
-4.2
+5.0
diff --git a/.travis.yml b/.travis.yml
index db60e3f..169099d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ os:
 language: generic
 sudo: required
 dist: trusty
-osx_image: xcode10.1
+osx_image: xcode10.2
 install:
   - if [[ "$TRAVIS_OS_NAME" != "osx" ]]; then eval "$(curl -sL https://swiftenv.fuller.li/install.sh)"; fi
 script:
diff --git a/Package.swift b/Package.swift
index c09db6e..fbf5d68 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,5 +1,4 @@
-// swift-tools-version:4.2
-// The swift-tools-version declares the minimum version of Swift required to build this package.
+// swift-tools-version:5.0
 
 import PackageDescription
 
@@ -11,5 +10,6 @@ let package = Package(
     targets: [
         .target(name: "ULID"),
         .testTarget(name: "ULIDTests", dependencies: ["ULID"])
-    ]
+    ],
+    swiftLanguageVersions: [.v5]
 )
diff --git a/Sources/ULID/Data+Base32.swift b/Sources/ULID/Data+Base32.swift
index fa89a39..c9f41f5 100644
--- a/Sources/ULID/Data+Base32.swift
+++ b/Sources/ULID/Data+Base32.swift
@@ -141,6 +141,7 @@ extension Data {
             defer { dst.deallocate() }
 
             let work = UnsafeMutablePointer<UInt8>.allocate(capacity: 8)
+            work.initialize(repeating: 0, count: 8)
             defer { work.deallocate() }
 
             while srcleft > 0 {
diff --git a/Tests/ULIDTests/Data+Base32Tests.swift b/Tests/ULIDTests/Data+Base32Tests.swift
index 6217b26..e0828d6 100644
--- a/Tests/ULIDTests/Data+Base32Tests.swift
+++ b/Tests/ULIDTests/Data+Base32Tests.swift
@@ -21,7 +21,7 @@ final class Base32Tests: XCTestCase {
             0x00, 0x00, 0x00, 0x00, 0x01, 0x68, 0x3D, 0xD4, 0x19, 0x86,
             0xFE, 0xB3, 0xF9, 0x57, 0xAF, 0x8B, 0x6F, 0x46, 0x79, 0x77
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual(expected, data.base32EncodedString())
     }
@@ -30,7 +30,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b11111000, 0b00000000, 0b00000000, 0b00000000, 0b00000000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("Z0000000", data.base32EncodedString())
     }
@@ -39,7 +39,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000111, 0b11000000, 0b00000000, 0b00000000, 0b00000000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("0Z000000", data.base32EncodedString())
     }
@@ -48,7 +48,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000000, 0b00111110, 0b00000000, 0b00000000, 0b00000000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("00Z00000", data.base32EncodedString())
     }
@@ -57,7 +57,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000000, 0b00000001, 0b11110000, 0b00000000, 0b00000000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("000Z0000", data.base32EncodedString())
     }
@@ -66,7 +66,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000000, 0b00000000, 0b00001111, 0b10000000, 0b00000000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("0000Z000", data.base32EncodedString())
     }
@@ -75,7 +75,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000000, 0b00000000, 0b00000000, 0b01111100, 0b00000000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("00000Z00", data.base32EncodedString())
     }
@@ -84,7 +84,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000000, 0b00000000, 0b00000000, 0b00000011, 0b11100000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("000000Z0", data.base32EncodedString())
     }
@@ -93,7 +93,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00011111
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("0000000Z", data.base32EncodedString())
     }
@@ -102,7 +102,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b10000100
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("GG======", data.base32EncodedString())
     }
@@ -111,7 +111,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b10000100, 0b00100001
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("GGGG====", data.base32EncodedString())
     }
@@ -120,7 +120,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b10000100, 0b00100001, 0b00001000
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("GGGGG===", data.base32EncodedString())
     }
@@ -129,7 +129,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b10000100, 0b00100001, 0b00001000, 0b01000010
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("GGGGGGG=", data.base32EncodedString())
     }
@@ -138,7 +138,7 @@ final class Base32Tests: XCTestCase {
         let bytes: [UInt8] = [
             0b10000100
         ]
-        let data = Data(bytes: bytes)
+        let data = Data(bytes)
 
         XCTAssertEqual("GG", data.base32EncodedString(padding: false))
     }
diff --git a/Tests/ULIDTests/ULIDTests.swift b/Tests/ULIDTests/ULIDTests.swift
index 91460b9..65237c6 100644
--- a/Tests/ULIDTests/ULIDTests.swift
+++ b/Tests/ULIDTests/ULIDTests.swift
@@ -67,7 +67,7 @@ final class ULIDTests: XCTestCase {
             0xE2, 0x56, 0xBA, 0xB4, 0xC3, 0x4C, 0x07, 0x57
         ]
 
-        let actual = ULID(ulidData: Data(bytes: expected))
+        let actual = ULID(ulidData: Data(expected))
 
         XCTAssertNotNil(actual)
         XCTAssertEqual(expected, Array(actual!.ulidData))
diff --git a/ULID.xcodeproj/project.pbxproj b/ULID.xcodeproj/project.pbxproj
index 404c991..8b66a6b 100644
--- a/ULID.xcodeproj/project.pbxproj
+++ b/ULID.xcodeproj/project.pbxproj
@@ -502,7 +502,7 @@
 				PRODUCT_NAME = ULID;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Debug;
 		};
@@ -528,7 +528,7 @@
 				PRODUCT_NAME = ULID;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Release;
 		};
@@ -549,7 +549,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "net.yaslab.ULIDTests-macOS";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Debug;
 		};
@@ -570,7 +570,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "net.yaslab.ULIDTests-macOS";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Release;
 		};