diff --git a/.travis.yml b/.travis.yml
index 3ff8969..2284728 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,15 @@
 language: objective-c # lol
-osx_image: xcode7.3
+osx_image: xcode8
 xcode_project: DVR.xcodeproj
 
+script: xcodebuild -scheme "$TRAVIS_XCODE_SCHEME" test
+
 matrix:
   include:
     - xcode_scheme: DVR-iOS
       xcode_sdk: iphonesimulator
     - xcode_scheme: DVR-OSX
       xcode_sdk: macosx
+
+env:
+  TOOLCHAINS=com.apple.dt.toolchain.Swift_2_3
diff --git a/DVR.xcodeproj/project.pbxproj b/DVR.xcodeproj/project.pbxproj
index e0fddb8..d80fe53 100644
--- a/DVR.xcodeproj/project.pbxproj
+++ b/DVR.xcodeproj/project.pbxproj
@@ -301,14 +301,16 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0700;
-				LastUpgradeCheck = 0700;
+				LastUpgradeCheck = 0800;
 				ORGANIZATIONNAME = Venmo;
 				TargetAttributes = {
 					3647AF9A1B335D5500EF10D4 = {
 						CreatedOnToolsVersion = 7.0;
+						LastSwiftMigration = 0800;
 					};
 					3647AFA41B335D5500EF10D4 = {
 						CreatedOnToolsVersion = 7.0;
+						LastSwiftMigration = 0800;
 					};
 					3690A07A1B33AA3B00731222 = {
 						CreatedOnToolsVersion = 7.0;
@@ -464,8 +466,10 @@
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
@@ -514,8 +518,10 @@
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
@@ -536,7 +542,7 @@
 				MACOSX_DEPLOYMENT_TARGET = 10.9;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
-				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 				VERSIONING_SYSTEM = "apple-generic";
@@ -548,6 +554,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
@@ -558,6 +565,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.venmo.DVR;
 				PRODUCT_NAME = DVR;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -565,6 +573,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
@@ -575,6 +584,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.venmo.DVR;
 				PRODUCT_NAME = DVR;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
@@ -586,6 +596,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.venmo.DVR.iostests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -597,6 +608,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.venmo.DVR.iostests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
@@ -616,6 +628,7 @@
 				PRODUCT_NAME = DVR;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -635,6 +648,7 @@
 				PRODUCT_NAME = DVR;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
@@ -648,6 +662,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.venmo.DVR.osxtests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -661,6 +676,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.venmo.DVR.osxtests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
diff --git a/DVR.xcodeproj/xcshareddata/xcschemes/DVR-OSX.xcscheme b/DVR.xcodeproj/xcshareddata/xcschemes/DVR-OSX.xcscheme
index 15505b8..1a99cd1 100644
--- a/DVR.xcodeproj/xcshareddata/xcschemes/DVR-OSX.xcscheme
+++ b/DVR.xcodeproj/xcshareddata/xcschemes/DVR-OSX.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0700"
+   LastUpgradeVersion = "0800"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -23,10 +23,10 @@
       </BuildActionEntries>
    </BuildAction>
    <TestAction
+      buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      shouldUseLaunchSchemeArgsEnv = "YES"
-      buildConfiguration = "Debug">
+      shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
             skipped = "NO">
@@ -52,11 +52,11 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
+      buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
-      buildConfiguration = "Debug"
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
@@ -74,10 +74,10 @@
       </AdditionalOptions>
    </LaunchAction>
    <ProfileAction
+      buildConfiguration = "Release"
       shouldUseLaunchSchemeArgsEnv = "YES"
       savedToolIdentifier = ""
       useCustomWorkingDirectory = "NO"
-      buildConfiguration = "Release"
       debugDocumentVersioning = "YES">
       <MacroExpansion>
          <BuildableReference
diff --git a/DVR.xcodeproj/xcshareddata/xcschemes/DVR-iOS.xcscheme b/DVR.xcodeproj/xcshareddata/xcschemes/DVR-iOS.xcscheme
index 5f0cb43..3171bfa 100644
--- a/DVR.xcodeproj/xcshareddata/xcschemes/DVR-iOS.xcscheme
+++ b/DVR.xcodeproj/xcshareddata/xcschemes/DVR-iOS.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0700"
+   LastUpgradeVersion = "0800"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -23,11 +23,11 @@
       </BuildActionEntries>
    </BuildAction>
    <TestAction
+      buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
-      codeCoverageEnabled = "YES"
-      buildConfiguration = "Debug">
+      codeCoverageEnabled = "YES">
       <Testables>
          <TestableReference
             skipped = "NO">
@@ -53,11 +53,11 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
+      buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
-      buildConfiguration = "Debug"
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
@@ -75,10 +75,10 @@
       </AdditionalOptions>
    </LaunchAction>
    <ProfileAction
+      buildConfiguration = "Release"
       shouldUseLaunchSchemeArgsEnv = "YES"
       savedToolIdentifier = ""
       useCustomWorkingDirectory = "NO"
-      buildConfiguration = "Release"
       debugDocumentVersioning = "YES">
       <MacroExpansion>
          <BuildableReference
diff --git a/DVR/Tests/SessionUploadTests.swift b/DVR/Tests/SessionUploadTests.swift
index f3009e8..99b841c 100644
--- a/DVR/Tests/SessionUploadTests.swift
+++ b/DVR/Tests/SessionUploadTests.swift
@@ -88,7 +88,10 @@ class SessionUploadTests: XCTestCase {
         let documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0]
         let documentsURL = NSURL(fileURLWithPath: documentsPath, isDirectory: true)
 
-        let url = documentsURL.URLByAppendingPathComponent(fileName + ".tmp")
+        guard let url = documentsURL.URLByAppendingPathComponent(fileName + ".tmp") else {
+            XCTFail("Failed to write to file")
+            fatalError()
+        }
 
         data.writeToURL(url, atomically: true)
         return url
diff --git a/Readme.markdown b/Readme.markdown
index c343ef7..6538873 100644
--- a/Readme.markdown
+++ b/Readme.markdown
@@ -8,9 +8,13 @@ watchOS, and OS X based on [VCR](https://github.com/vcr/vcr).
 Easy [dependency injection](https://en.wikipedia.org/wiki/Dependency_injection) is the main design goal. The API is the same as `NSURLSession`. `DVR.Session` is a subclass of `NSURLSession` so you can use it as a drop in replacement anywhere. (Currently only data tasks are supported.)
 
 
-## Building
+## Version Compatibility
 
-DVR 0.3.0 requires Swift 2.2. For older versions of Swift, please use 0.2.x.
+| Swift Version | DVR Version |
+| ------------- | ----------- |
+| 2.3           | 0.4         |
+| 2.2           | 0.3         |
+| < 2.2         | 0.2.1       |
 
 
 ## Usage