Code Migration from Swift 2.X to Swift 4

Code migration from Swift 2.x to Swift 4

Yes, you must migrate your code in Swift 3 compatible version. Xcode 9 allows conversion/migration from swift 3.0 only.

Swift 3.2 is supported by Xcode 9 & Xcode 8 both.

Convert your source code from Swift 2.0 to 3.2 using Xcode 8 and then continue with Xcode 9 (Swift 3.2 or 4).

For easier migration of your code, follow these steps: (it will help you to covert into latest version of swift supported by your Xcode Tool)

(Xcode) Menus: Edit ► Covert ► To Current Swift Syntax

Code migration from Swift 2.x to Swift 4 (for loop)

Here's your statement in Swift 4:

for i in 1..<dataByLine.count {

}

How to migrate a code from swift 3 to swift 4 or above?

You cannot run swift 3 on Xcode 11. Download a version of XCode 10.1,You can run both.There will be option to migrate code to swift 4.

here you can download XCode 10.1:

XCode 10.1

Please check this link below. You can upgrade to swift 4.

https://medium.com/@hanif.awan2007/tips-upgrading-your-code-from-swift-3-to-swift-4-dbcba128b48b

iOS: Migration (Upgrade) from Swift 3 to Swift 4

We have a better option to fix this error at once. It can be solved out from Editor menu

Use this option to fix all the error at once in class.

Note: You cannot always rely on Xcode suggestions, but for migration case it will work in most of the case.

How can change Swift 3 to 4 in Xcode 11.4

There are 2 ways you can do the migration

1. Use Xcode 10.1's migration tool to update your code-base directly to swift4
   But this will still require manual pod update

2. If your code-base is small, you can skip the hassle of downloading and installing of Xcode and could manually update code to swift 4 by refactoring.

Follow this tutorial, It is comprehensive enough for migration

When migrating to Swift 4, do I need to update 3.0 to 3.2?

If you are talking about translating your project in XCode from an earlier version of swift to the most recent, then no you do not need to update it to something in between, Xcode will do it for you. Even if I am wrong and you did, Xcode will automatically do it for you. Keep in mind it will do the best it can but some things have changed dramatically. It is best to be familiar with the language and try to work on migrating your code piece by piece. I myself experienced this with an old project, where I had to take several classes a day and translate them until they no longer gave me errors. Took me about 4 days, where the amount of time it took was about 2-4 files an hour.

There is a big difference between needing to upgrade swift and needing to upgrade Xcode. Just take this with blind faith. Upgrade Xcode first always and make sure you do it completely. Then migrate swift. You are misunderstanding. The way swift is made, it does not matter if your code is 2.4, 3.1, 3.8. Upgrading to the newest version will be the same process. The only difference when upgrading from various lower version to the newest is that you have to convert from what ever version you are currently at to the newest version. Also if you are worried about making mistakes when you update then I strongly recommend that you save your project with source control. If you are unfamiliar with source control, then just alway have a backup copy of your original project before you started messing with it (I always found a way to mess stuff up doing it that way though, so just be really careful. I found using a separate flash drive prevented me from making silly mistakes).

Also, after reading the comments. I wanted to note that YOU SHOULD UPDATE YOUR OS FIRST lol. I guess I just kind of assumed that you had already done that XD

Is it mandatory to convert to Swift 4? should I convert even if it's not mandatory?

It it not mandatory to convert to Swift 4... yet. If you read the release notes for the upcoming release of Xcode 10 you will see that Xcode 10 will be the last release to support Swift 3. Xcode release cadence runs about one major release per year so a good estimate for the deprecation of Swift 3 is September 2019. The difficulty of migrating from Swift 3 to Swift 4 is commonly reported on industry blogs as being less difficult than previous releases such as moving from Swift 2 to Swift 3.

---

Related Topics