How to See Which Version of Swift I'M Using

How do I see which version of Swift I'm using?

Project build settings have a block 'Swift Compiler - Languages', which stores information about Swift Language Version in key-value format. It will show you all available (supported) Swift Language Version for your Xcode and active version also by a tick mark.

Project ► (Select Your Project Target) ► Build Settings ► (Type
'swift_version' in the Search bar) Swift Compiler Language ► Swift Language
Version ► Click on Language list to open it (and there will be a tick mark on any one of list-item, that will be current swift version).

Look at this snapshot, for easy understanding:

xcode with described areas highlighted

With help of following code, programmatically you can find Swift version supported by your project.

#if swift(>=5.7)
print("Hello, Swift 5.7")

#elseif swift(>=5.6)
print("Hello, Swift 5.6")

#elseif swift(>=5.5)
print("Hello, Swift 5.5")

#elseif swift(>=5.4)
print("Hello, Swift 5.4")

#elseif swift(>=5.3)
print("Hello, Swift 5.3")

#elseif swift(>=5.2)
print("Hello, Swift 5.2")

#elseif swift(>=5.1)
print("Hello, Swift 5.1")

#elseif swift(>=5.0)
print("Hello, Swift 5.0")

#elseif swift(>=4.2)
print("Hello, Swift 4.2")

#elseif swift(>=4.1)
print("Hello, Swift 4.1")

#elseif swift(>=4.0)
print("Hello, Swift 4.0")

#elseif swift(>=3.2)
print("Hello, Swift 3.2")

#elseif swift(>=3.0)
print("Hello, Swift 3.0")

#elseif swift(>=2.2)
print("Hello, Swift 2.2")

#elseif swift(>=2.1)
print("Hello, Swift 2.1")

#elseif swift(>=2.0)
print("Hello, Swift 2.0")

#elseif swift(>=1.2)
print("Hello, Swift 1.2")

#elseif swift(>=1.1)
print("Hello, Swift 1.1")

#elseif swift(>=1.0)
print("Hello, Swift 1.0")


Here is result using Playground (with Xcode 11.x)

Sample Image

How can I programmatically find Swift's version?

Swift 3.1 extends the @available attribute to support specifying Swift version numbers in addition to its existing platform versions.

// Swift 3.1

@available(swift 3.1)
func intVersion(number: Double) -> Int? {
return Int(exactly: number)

@available(swift, introduced: 3.0, obsoleted: 3.1)
func intVersion(number: Double) -> Int {
return Int(number)

How do I get the App version and build number using Swift?


Updated for Swift 4.2

let appVersion = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String


As pointed out by @azdev on the new version of Xcode you will get a compile error for trying my previous solution, to solve this just edit it as suggested to unwrap the bundle dictionary using a !

let nsObject: AnyObject? = Bundle.main.infoDictionary!["CFBundleShortVersionString"]

End Edit

Just use the same logic than in Objective-C but with some small changes

//First get the nsObject by defining as an optional anyObject
let nsObject: AnyObject? = NSBundle.mainBundle().infoDictionary["CFBundleShortVersionString"]

//Then just cast the object as a String, but be careful, you may want to double check for nil
let version = nsObject as! String

Check OS version in Swift?

For iOS, try:

var systemVersion = UIDevice.current.systemVersion

For OS X, try:

var systemVersion = NSProcessInfo.processInfo().operatingSystemVersion

If you just want to check if the users is running at least a specific version, you can also use the following Swift 2 feature which works on iOS and OS X:

if #available(iOS 9.0, *) {
// use the feature only available in iOS 9
// for ex. UIStackView
} else {
// or use some work around

BUT it is not recommended to check the OS version. It is better to check if the feature you want to use is available on the device than comparing version numbers.
For iOS, as mentioned above, you should check if it responds to a selector;

if (self.respondsToSelector(Selector("showViewController"))) {
self.showViewController(vc, sender: self)
} else {
// some work around

What is the Swift Language Version Xcode setting for? Because it still builds newer Swift code with an older version set

Prior to Swift 4, the version of the compiler and the language were one and the same. But since Swift 4, the compiler can run in a compatibility mode for previous Swift versions. check more info on compatibility modes in the Swift 4.0 release notes

The Xcode build setting SWIFT_VERSION set's the compiler flag -swift-version which is the language mode. From the swift compiler print out below this parameter only changes how the input is interpreted.

swiftc -h|grep 'Swift language version number'
-swift-version <vers> Interpret input according to a specific Swift language version number

Thus When you select Swift Language Version to 4.2, this does not mean use Swift 4.2 compiler. The compiler version will still be 5.1.3, the Swift Language Version setting instructs the compiler to run in Swift 4.2 compatibility mode. The compatibility mode means you may not need to modify your swift 4.2 code to use the new version of the compiler. Because the compiler running in compatibility mode allows Swift version 4.2 code to compile and run alongside code from version 5 and later.

compiler options

The Swift 5 compiler with compatibility mode can compile code written with either Swift 4 syntax, Swift 4.2 syntax, or Swift 5 syntax.

Here is a code example, create a file test.swift with code below:

//code written before siwft 5
let firstName = "michael jackson"
let offset = firstName.endIndex.encodedOffset

// Check swift version being used.
#if swift(>=5.2)
print("Hello, Swift 5.2")

#elseif swift(>=5.1)
print("Hello, Swift 5.1")

#elseif swift(>=5.0)
print("Hello, Swift 5.0")

#elseif swift(>=4.2)
print("Hello, Swift 4.2")

#elseif swift(>=4.1)
print("Hello, Swift 4.1")

#elseif swift(>=4.0)
print("Hello, Swift 4.0")


suppose the above code was written before swift 5 using the swift 4 compiler
this code will compile with no error's as shown below.

Sample Image

After swift 5 is released if you try to compile this code with Swift 5 compiler as shown below.

Swift 5 compiler

You will get the warning shown above since encodedOffset is deprecated in swift 5.

You could downgrade and use the swift 4 compiler or you can use the Swift 5 compiler in compatibility mode with the compiler flag -swift-version as shown below.

Swift 5 compiler with compatibility mode

It's important to note that Swift 4 compiler, and the Swift 5 compiler in Swift-4 compatibility mode are not the same thing. New swift 5 language features are normally available to the swift 5 compiler running compatibility mode. This allows developers to use the new features even when they can't upgrade to swift 5. The new Swift 5 features will not be available to the Swift 4 compiler.

How can I choose Swift compiler version

Originally I posted this is a comment, but I should have just posted it as an answer:

If you're writing an app for the App Store, you can only use a release (non-beta) version of Xcode (see “Submitting Apps to the App Store using Xcode”) and the toolchain supplied with that version of Xcode (see “Using Downloads / Apple Platforms”). So you can either use Xcode 7.2 and continue using Swift 2.1, or you can use Xcode 7.3 and update your code to Swift 2.2.

You can have multiple versions of Xcode installed. You can keep Xcode 7.2 installed and use it for your non-updated Swift 2.1 projects, and use Xcode 7.3 on new projects. Note that you'll have to manually open each project in the appropriate version of Xcode. You can download old versions of Xcode here.

If you're not going to put your app in the App Store, then maybe you could extract the Swift 2.1 toolchain from the Xcode 7.2 bundle and turn it into a .xctoolchain for use with Xcode 7.3, but you're really in unexplored, unsupported territory if you go that route.

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