diff --git a/Cartfile.resolved b/Cartfile.resolved
index fe4efefb..2f59c33f 100644
--- a/Cartfile.resolved
+++ b/Cartfile.resolved
@@ -1,3 +1,3 @@
-github "antitypical/Result" "2.0.0"
-github "SwiftyJSON/SwiftyJSON" "2.3.3"
-github "Thomvis/BrightFutures" "v4.0.1"
+github "antitypical/Result" "2.1.3"
+github "SwiftyJSON/SwiftyJSON" "2.4.0"
+github "Thomvis/BrightFutures" "v4.1.1"
diff --git a/Spine.xcodeproj/project.pbxproj b/Spine.xcodeproj/project.pbxproj
index 97835778..bfd18906 100644
--- a/Spine.xcodeproj/project.pbxproj
+++ b/Spine.xcodeproj/project.pbxproj
@@ -611,9 +611,11 @@
 					};
 					D373F78719B2249900275AFC = {
 						CreatedOnToolsVersion = 6.0;
+						LastSwiftMigration = 0800;
 					};
 					D373F79219B2249900275AFC = {
 						CreatedOnToolsVersion = 6.0;
+						LastSwiftMigration = 0800;
 					};
 				};
 			};
@@ -1170,6 +1172,7 @@
 				PRODUCT_NAME = Spine;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -1191,6 +1194,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.wardvanteijlingen.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = Spine;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
@@ -1210,6 +1214,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.wardvanteijlingen.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -1225,6 +1230,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.wardvanteijlingen.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
diff --git a/Spine/Routing.swift b/Spine/Routing.swift
index 8904dafd..a3db5b6f 100644
--- a/Spine/Routing.swift
+++ b/Spine/Routing.swift
@@ -66,7 +66,7 @@ public class JSONAPIRouter: Router {
 	public init() { }
 	
 	public func URLForResourceType(type: ResourceType) -> NSURL {
-		return baseURL.URLByAppendingPathComponent(type)
+		return baseURL.URLByAppendingPathComponent(type)!
 	}
 	
 	public func URLForRelationship<T: Resource>(relationship: Relationship, ofResource resource: T) -> NSURL {
@@ -76,8 +76,8 @@ public class JSONAPIRouter: Router {
 		
 		let resourceURL = resource.URL ?? URLForResourceType(resource.resourceType).URLByAppendingPathComponent("/\(resource.id!)")
 		let key = keyFormatter.format(relationship)
-		let urlString = resourceURL.URLByAppendingPathComponent("/relationships/\(key)").absoluteString
-		return NSURL(string: urlString, relativeToURL: baseURL)
+		let urlString = resourceURL!.URLByAppendingPathComponent("/relationships/\(key)")!.absoluteString
+		return NSURL(string: urlString!, relativeToURL: baseURL)!
 	}
 
 	
@@ -137,9 +137,9 @@ public class JSONAPIRouter: Router {
 			let fieldName = filter.leftExpression.keyPath
             var item: NSURLQueryItem?
             if let field = T.fieldNamed(fieldName) {
-                item = queryItemForFilter(field, value: filter.rightExpression.constantValue, operatorType: filter.predicateOperatorType)
+                item = queryItemForFilter(field, value: filter.rightExpression.constantValue!, operatorType: filter.predicateOperatorType)
             } else {
-                item = queryItemForFilterName(fieldName, value: filter.rightExpression.constantValue, operatorType: filter.predicateOperatorType)
+                item = queryItemForFilterName(fieldName, value: filter.rightExpression.constantValue!, operatorType: filter.predicateOperatorType)
             }
 			setQueryItem(item!, forQueryItems: &queryItems)
 		}
diff --git a/Spine/ValueFormatter.swift b/Spine/ValueFormatter.swift
index 14ec125e..bab326d3 100644
--- a/Spine/ValueFormatter.swift
+++ b/Spine/ValueFormatter.swift
@@ -145,7 +145,7 @@ private struct URLValueFormatter: ValueFormatter {
 	}
 	
 	func format(value: NSURL, attribute: URLAttribute) -> AnyObject {
-		return value.absoluteString
+		return value.absoluteString ?? ""
 	}
 }