diff --git a/ObjectMapper.xcodeproj/project.pbxproj b/ObjectMapper.xcodeproj/project.pbxproj
index 8e6e8c6d..ddbdf27b 100644
--- a/ObjectMapper.xcodeproj/project.pbxproj
+++ b/ObjectMapper.xcodeproj/project.pbxproj
@@ -728,11 +728,11 @@
 					};
 					6AAC8F7519F03C2900E7A677 = {
 						CreatedOnToolsVersion = 6.0.1;
-						LastSwiftMigration = 0900;
+						LastSwiftMigration = 1020;
 					};
 					6AAC8F8019F03C2900E7A677 = {
 						CreatedOnToolsVersion = 6.0.1;
-						LastSwiftMigration = 0900;
+						LastSwiftMigration = 1020;
 					};
 					CD1602FE1AC023D5000CD69A = {
 						CreatedOnToolsVersion = 6.2;
@@ -1363,8 +1363,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.tristanhimmelman.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(PROJECT_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TVOS_DEPLOYMENT_TARGET = 9.0;
 				WATCHOS_DEPLOYMENT_TARGET = 2.0;
 			};
@@ -1385,8 +1384,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.tristanhimmelman.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(PROJECT_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TVOS_DEPLOYMENT_TARGET = 9.0;
 				WATCHOS_DEPLOYMENT_TARGET = 2.0;
 			};
@@ -1404,8 +1402,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.heart.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Debug;
 		};
@@ -1417,8 +1414,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.heart.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Release;
 		};
diff --git a/Sources/ISO8601DateTransform.swift b/Sources/ISO8601DateTransform.swift
index 1f256ea8..cf586420 100644
--- a/Sources/ISO8601DateTransform.swift
+++ b/Sources/ISO8601DateTransform.swift
@@ -29,7 +29,7 @@
 import Foundation
 
 public extension DateFormatter {
-	convenience init(withFormat format : String, locale : String) {
+	@objc convenience init(withFormat format : String, locale : String) {
 		self.init()
 		self.locale = Locale(identifier: locale)
 		dateFormat = format
diff --git a/Sources/ImmutableMappable.swift b/Sources/ImmutableMappable.swift
index 1f678245..b6e7c7e6 100644
--- a/Sources/ImmutableMappable.swift
+++ b/Sources/ImmutableMappable.swift
@@ -272,7 +272,7 @@ public extension Mapper where N: ImmutableMappable {
 		#if swift(>=4.1)
 		return try JSONArray.compactMap(mapOrFail)
 		#else
-		return try JSONArray.flatMap(mapOrFail)
+		return try JSONArray.compactMap(mapOrFail)
 		#endif
 	}
 	
diff --git a/Sources/Map.swift b/Sources/Map.swift
index 38dc2a3f..a18ffb9e 100644
--- a/Sources/Map.swift
+++ b/Sources/Map.swift
@@ -134,7 +134,7 @@ public final class Map {
 				#if swift(>=4.1)
 				return v.compactMap{ Float($0) } as? T
 				#else
-				return v.flatMap{ Float($0) } as? T
+				return v.compactMap{ Float($0) } as? T
 				#endif
 			}
 		} else if value == nil && T.self == [String:Float].self {
diff --git a/Sources/Mapper.swift b/Sources/Mapper.swift
index cccbdcee..e548ef64 100755
--- a/Sources/Mapper.swift
+++ b/Sources/Mapper.swift
@@ -165,7 +165,7 @@ public final class Mapper<N: BaseMappable> {
 		#if swift(>=4.1)
 		let result = JSONArray.compactMap(map)
 		#else
-		let result = JSONArray.flatMap(map)
+		let result = JSONArray.compactMap(map)
 		#endif
 		return result
 	}
@@ -433,7 +433,7 @@ extension Mapper where N: Hashable {
 		#if swift(>=4.1)
 		return Set(JSONArray.compactMap(map))
 		#else
-		return Set(JSONArray.flatMap(map))
+		return Set(JSONArray.compactMap(map))
 		#endif
 	}
 
diff --git a/Sources/ToJSON.swift b/Sources/ToJSON.swift
index 674db27f..08813819 100644
--- a/Sources/ToJSON.swift
+++ b/Sources/ToJSON.swift
@@ -48,7 +48,7 @@ private func setValue(_ value: Any, forKeyPathComponents components: ArraySlice<
 
 	let headAsString = String(head)
 	if components.count == 1 {
-		dictionary[headAsString] = value
+                dictionary[headAsString] = value
 	} else {
 		var child = dictionary[headAsString] as? [String : Any] ?? [:]
 		
diff --git a/Sources/TransformOperators.swift b/Sources/TransformOperators.swift
index 1c55f9b9..c7dd63f9 100644
--- a/Sources/TransformOperators.swift
+++ b/Sources/TransformOperators.swift
@@ -504,7 +504,7 @@ public func <- <Transform: TransformType>(left: inout [[Transform.Object]], righ
 			fromJSONArrayWithTransform(values as Any?, transform: transform)
 		}
 		#else
-		let transformed2DArray = original2DArray.flatMap { values in
+		let transformed2DArray = original2DArray.compactMap { values in
 			fromJSONArrayWithTransform(values as Any?, transform: transform)
 		}
 		#endif
@@ -522,7 +522,7 @@ public func >>> <Transform: TransformType>(left: [[Transform.Object]], right: (M
 			toJSONArrayWithTransform(values, transform: transform)
 		}
 		#else
-		let transformed2DArray = left.flatMap { values in
+		let transformed2DArray = left.compactMap { values in
 			toJSONArrayWithTransform(values, transform: transform)
 		}
 		#endif
@@ -543,7 +543,7 @@ public func <- <Transform: TransformType>(left: inout [[Transform.Object]]?, rig
 			fromJSONArrayWithTransform(values as Any?, transform: transform)
 		}
 		#else
-		let transformed2DArray = original2DArray.flatMap { values in
+		let transformed2DArray = original2DArray.compactMap { values in
 			fromJSONArrayWithTransform(values as Any?, transform: transform)
 		}
 		#endif
@@ -561,7 +561,7 @@ public func >>> <Transform: TransformType>(left: [[Transform.Object]]?, right: (
 			toJSONArrayWithTransform(values, transform: transform)
 		}
 		#else
-		let transformed2DArray = left?.flatMap { values in
+		let transformed2DArray = left?.compactMap { values in
 			toJSONArrayWithTransform(values, transform: transform)
 		}
 		#endif
@@ -671,7 +671,7 @@ private func fromJSONArrayWithTransform<Transform: TransformType>(_ input: Any?,
 			return transform.transformFromJSON(value)
 		}
 		#else
-		return values.flatMap { value in
+		return values.compactMap { value in
 			return transform.transformFromJSON(value)
 		}
 		#endif
@@ -696,7 +696,7 @@ private func toJSONArrayWithTransform<Transform: TransformType>(_ input: [Transf
 		return transform.transformToJSON(value)
 	}
 	#else
-	return input?.flatMap { value in
+	return input?.compactMap { value in
 		return transform.transformToJSON(value)
 	}
 	#endif