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The Kotlin YouTube Channel

The Kotlin community has always been the greatest source of inspiration for our team. We aspire to make the life of every Kotlin developer better, and we do our best to listen to all your feedback. With the increasing demand for more Kotlin-related video content, we would like to draw your attention to the Kotlin YouTube channel. It will help you connect with other Kotlin enthusiasts, stay up to date with what we are doing in the Kotlin team, and learn new skills from the comfort of your couch.

The Kotlin YouTube channel was launched on January 18, 2021, and has since grown to have more than 9 thousand subscribers, who can expect a new video every week. Over these 2 and a half months, we have introduced a multitude of formats, including pre-recorded videos, live webinars, and a bi-weeikly video podcast.

Subscribe to the Kotlin YouTube channel!

Here is a short summary of all of the series and formats that are currently available:

Spring Time in Kotlin

In this series you will learn how Kotlin and Spring work hand-in-hand to make you more productive while building server-side applications. Together with Anton Arhipov you will build a simple service with a database and extend it to try different Spring APIs. All the episodes are accompanied by code samples, so it will be easy for you to follow along and start using Kotlin to build Spring applications.

Webinars with experts

During our webinars, experts from different companies explain how to use Kotlin for a variety of purposes and answer questions during Q&A sessions. Speakers from JetBrains, VMware, Confluent, and Oracle have covered reactive programming, asynchronous applications with the Ktor framework, building microservices with Helidon, and other aspects of using Kotlin for server-side development. There are also special tracks on competitive programming and Kotlin for education, and more webinars are still to come! Subscribe to take part in the webinars and ask your questions during the live Q&A sessions! Recordings of these events will be also available after on the channel.

Kotlin Standard Library Safari

Learn about the features you get out of the box with Kotlin! If you know how to wield it, the Kotlin standard library is a powerful tool that can help you solve problems more effectively and be more expressive in your code. Together with Sebastian Aigner, we go through the useful functionality the standard library in Kotlin has to offer. In the process, we together unearth some hidden gems that could come in handy the next time you write Kotlin code.

Talking Kotlin

Since 2017, the Talking Kotlin Podcast has been the place to hear from people of different backgrounds and specializations about how they use Kotlin. Following its move to YouTube, Sebastian Aigner has joined Hadi Hariri as a co-host and we have already had conversations about the present and the future of Kotlin with its new project lead, Roman Elizarov, and about Kotlin Multiplatform with John O’Reilly. In each episode we are joined by interesting guests who offer insights into their experiences of using Kotlin in a variety of exciting fields.

Kotlin Multiplatform Multiverse

In this series of videos, Kate Petrova will show you how to use Kotlin Multiplatform Mobile for developing apps for iOS and Android from a single codebase. You will start by creating a simple application and proceed to look at a typical KMM-project structure. After learning the basics of KMM, you will see how to use it in real projects and understand how to make the process of developing cross-platform mobile apps with Kotlin Multiplatform efficient and enjoyable.

Plans for the future

We’re not stopping there. We’re exploring additional formats that will allow us to provide even more Kotlin content for you to enjoy. We have plans to bring more people from the team to the channel and organize special video events dedicated to certain milestones in the language. For example, we plan to do something special for the upcoming Kotlin 1.5 release.

Subscribe to our YouTube channel to never miss a thing!

As we continue to develop the official YouTube channel for Kotlin, we would like to pause for a moment to say thank you to everyone who inspired us to make all of this happen. We love reading your comments under the videos, and we continuously strive to make the channel better and provide content that you, our community, will find helpful. Please leave your ideas for a new series here, or under any of our videos, and we’ll do our best to bring them to the channel.

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New Release Cadence for Kotlin and the IntelliJ Kotlin Plugin


  1. From now on, we will release Kotlin 1.X every six months. These releases will be date-driven, not feature-driven.
  2. The Kotlin IDE plugin will be released simultaneously with Kotlin, and on top of that — every time IntelliJ IDEA is released. Major IDE features will arrive in releases synchronized with IntelliJ IDEA.

Why the new cadence?

Since Kotlin 1.0 came out in 2016, we’ve built our release schedule around new key features in the language. This meant that until big language features were ready we would not release anything at all. As a consequence, we delivered changes and improvements once a year or sometimes even less frequently. The language has evolved more slowly than we would like, and release dates have been somewhat unpredictable for the users.

The main goal of the new date-driven release cadence is to accelerate the delivery of important language updates.

What are the changes in the new cadence?

There are three types of Kotlin releases: feature, incremental, and bug fix releases. However, changes will, for the most part, only affect feature releases. Below is a diagram of the new Kotlin release cadence.

Feature releases (e.g. 1.4, 1.5) will ship updates to the language twice a year– in spring and in autumn – starting from Kotlin 1.5, which is due in spring 2021. Feature releases will become smaller in terms of the changes they bring, and their release dates will be more predictable.

Incremental releases (e.g. 1.3.70, 1.4.20) will ship in between major releases. They will not include language changes, only compiler improvements (e.g. speedups) and tooling changes.

Bug fix releases (e.g. 1.3.71, 1.3.72) will possibly, but not necessarily, follow incremental releases. They mainly contain hotfixes.

Extra notes on the Kotlin IDE plugin

Nowadays, major changes in the Kotlin IDE plugin depend on the IntelliJ Platform more than on the Kotlin compiler. So, from now on, new versions of the Kotlin plugin will ship with every release of the IntelliJ Platform as well as with new versions of Kotlin.

At all times, the IDE support for the latest version of the language will be available for the two latest versions of IntelliJ IDEA and the latest version of Android Studio.

We are in the process of moving the Kotlin IDE plugin to the IntelliJ IDEA codebase to minimize the time it takes us to pick up platform changes, and also make sure that the IntelliJ team gets the latest Kotlin IDE fixes very quickly and dogfoods them efficiently. Also, it will be easier for us to keep the IDE support for Kotlin on par with Java. This is why we synchronize our release cycles.


Kotlin is evolving quickly and we’re keen to remove any obstacles preventing the team and the community from achieving their goals. Today we’ve introduced two major process improvements, and we believe they will speed up the language progress even more.

If you are interested in the Kotlin team’s plans and the projects we’re currently working on, you can find more information in the recently published Kotlin public roadmap.

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Kotlin 1.4 Released with a Focus on Quality and Performance

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Today we’re releasing Kotlin 1.4.0! Over the past years, we’ve been working hard on making Kotlin a programming language that is fun, enjoyable, and productive to work with. To continue our pursuit of this goal with this version of Kotlin, we put a lot of energy and effort into improving the performance and quality of Kotlin and its tooling. We are also excited to announce support for several new language features, including the long-awaited SAM conversions for Kotlin interfaces.


To help you get the most out of the changes and improvements introduced in Kotlin 1.4, we’re inviting all of you to the Kotlin 1.4 Online Event, where you will be able to enjoy four days of Kotlin talks, Q&As with the Kotlin team, and more – completely free.

Community and ecosystem

More than 5.8 million people have edited Kotlin code in the last 12 months, and the numbers are constantly growing:


We’re delighted to see how popular Kotlin is becoming! The numbers of active users – we’ll explain this metric in more detail in a future blog post – have been especially encouraging. Here, we are seeing a 1.5-fold increase over the previous year’s figures.

According to the StackOverflow Developer Survey 2020, Kotlin has climbed to 13th place among the most popular programming languages for professional developers, and we’re happy to see that Kotlin is one of the top 5 most loved languages.

Many companies have picked Kotlin as their language of choice, and are successfully using it on all platforms. We’re happy to see this tendency, and we’re tremendously grateful that so many of these companies have made case studies available for the community to read and learn from. Here are just a few amazing examples of software recently developed in Kotlin:

Our Kotlin communities are also growing rapidly. Over 30,000 Kotlin developers are now exchanging knowledge and supporting each other on Slack and Reddit, and more than 90,000 people follow our official Twitter account for tips, tricks, and announcements. With over 200 user groups worldwide, the Kotlin community is thriving and growing. We’re thankful to all of you for helping spread the word, sharing your knowledge, and supporting your fellow Kotlin developers. The warm, welcoming atmosphere you create is what makes exploring Kotlin together such a delightful experience. It wouldn’t be the same without you.

Kotlin 1.4 Online Event

We want to make sure that you have a great experience using Kotlin 1.4, and we want you to have a good idea of where we are taking the language next. This is why we are happy to invite all of you to our Kotlin 1.4 Online Event!

It consists of four days packed with knowledge about Kotlin and the future of the language and its ecosystem: We’ll discuss the new changes and improvements we made with Kotlin 1.4, and we’ll share our future plans for the language. Our Kotlin team members will answer your questions in daily Q&A sessions. Submit your questions in advance by tweeting them with the #kotlin14ask hashtag, or using this form.

The Kotlin 1.4 Online Event will be streamed on October 12–15, and you can register for free here:

Register for Kotlin 1.4 Online Event

We look forward to seeing all of you there!

Focusing on quality

Our main focus for this release was improving the overall development experience with Kotlin, including improved IDE performance and stability. Our goal is to make Kotlin users as productive as possible, and we focused on improving the things that are most important to users, so they feel even happier when using it!

We’ve reviewed and fixed more than 60 performance issues, including many that were causing IDE freezes or memory leaks. During the EAP phase for Kotlin 1.4.0, we gathered a lot of positive feedback indicating that the overall experience is now much more enjoyable!

When you are working with a project and open a large Kotlin file for the first time, you now see its content with highlighting much sooner. In most cases, highlighting is now 1.5-4 times faster:

We have also significantly improved the time it takes for autocomplete suggestions to appear. The following graph shows an overview of the average autocomplete response times that Kotlin users experience. The number of cases in which completion takes more than 500 ms has been cut nearly in half:


Note that these latest changes, including the code highlighting speed-up, require IntelliJ IDEA 2020.1+ and Android Studio 4.1+.

Performance improvements are an ongoing process, and we have many more enhancements planned, like continuing to work on eliminating freezing and making typing smoother. We’ve already started integration with the new experimental Kotlin compiler frontend that will make the IDE a lot faster. This is a huge task that requires many parts of the plugin to be rewritten, but it will boost performance in many areas of the IDE, including code completion, syntax highlighting, and compiler error reporting.

New IDE functionality

Our mission at JetBrains is to make software development a more productive and enjoyable experience, so we naturally want to make sure that the tooling surrounding Kotlin is excellent and makes coding Kotlin as easy as possible.

To make it easier for you to work with coroutines, and especially to pinpoint bugs in your concurrent applications, we’ve introduced the Coroutine Debugger. We’re going to expand on its initial feature set to provide the functionality most needed by the community, so please share your feedback with us using one of our channels or in the comments section below.

We are also introducing a new flexible Kotlin Project Wizard. This new wizard provides a single place for you to create and configure Kotlin projects of different types, making it easy to get started even with more complex structures such as multiplatform projects.

More than 40 new quick-fixes, intentions, and inspections have been added with Kotlin 1.4.0, and will be available exactly when you need them – when you modify your code, and press Alt+Enter to see what’s available in your specific context.

New compiler

For quite some time now, we’ve been working on a new Kotlin compiler that will advance the evolution of Kotlin in terms of performance and extensibility. The main goals for the new compiler are that it should be really fast, unify all the platforms that Kotlin supports, and provide an API for compiler extensions. We’re introducing new parts step by step, so that they reach the user as soon as possible. With Kotlin 1.4.0, we’re releasing several parts from this ongoing effort:

We’re actively working on a new frontend implementation, which will provide the biggest performance increase in the compiler pipeline. The frontend is the part of the compiler that parses the code, resolves names, performs type checking, and more, so it affects the IDE performance as well. A preview of it will be available in future releases, stay tuned!

Language features

Kotlin 1.4 comes with many new features:

Library improvements

Our general priority for the standard library is to improve consistency, both across different platforms and among the operations themselves. In this release, the Kotlin standard library gets new collection operators, delegated properties improvements, the double-ended queue implementation


, and much more.

You can use the standard library in “common” code – the code shared between different platforms, be they Android & iOS or JVM & JS. We’re gradually extending the common library and adding or moving missing functionality to it.

It is also no longer necessary to declare a dependency on the


in any Gradle Kotlin project, whether you are targeting a single platform or working in a multiplatform project. Starting with Kotlin 1.4.0, this dependency is added by default.

We’re working on other parts of the Kotlin ecosystem:


We encourage you to try out the new Alpha Kotlin/JVM backend for your regular projects and share your feedback! Along with unifying the compiler pipelines, this effort will help us bring compiler extensions like Jetpack Compose to the Kotlin community more quickly.

Language features specific to Kotlin/JVM:


Kotlin 1.4.0 comes with a new Gradle DSL and an Alpha version of the new Kotlin/JS compiler backend, among other features.

  • The new Gradle DSL adds support for configuring CSS and style loaders from the DSL, it includes various improvements related to npm dependency management and improves control over the Dukat integration.
  • The new Kotlin/JS compiler backend gives a taste of the future for Kotlin/JS. It includes optimizations and features such as the automatic generation of TypeScript definitions from Kotlin code, smaller binaries and bundles, a modernized way to expose Kotlin functionality to JavaScript, and more.


Kotlin/Native got a significant number of new features and improvements, including:

The current automatic memory management implementation in Kotlin/Native has limitations when it comes to concurrency and we are working on a replacement for it.

An important focus for Kotlin/Native is making it seamless for Kotlin Multiplatform Mobile, but it’s not limited to this.

Kotlin Multiplatform

Making Kotlin a great multiplatform solution is one of our top priorities. We promised some important improvements at KotlinConf, and we’re happy to report on what we’ve delivered:

We’re working on an Android Studio plugin for running, testing, and debugging Kotlin code on iOS devices and simulators. The first public preview is going to be released very soon, so please stay tuned.

We’re soon going to release a bunch of materials created with the help of Kotlin community members explaining how you can use Kotlin Multiplatform Mobile (KMM) technology to target specifically mobile use-cases in which code is shared between Android and iOS.

Despite the major focus now being on mobile targets, the Web target for Kotlin Multiplatform is already actively used by JetBrains to build and ship JetBrains Space. Web target continues to be an important strategic investment for Kotlin.

More details

You can find detailed descriptions of new features on the Kotlin 1.4 What’s New page and documentation, and read more about migrating to Kotlin 1.4.

As in all major releases, some deprecation cycles of previously announced changes are coming to an end with Kotlin 1.4. All of these cases were carefully reviewed by the language committee and are listed in the Compatibility Guide for Kotlin 1.4.

How to help us improve Kotlin

The Kotlin plugin in IntelliJ IDEA and Android Studio can collect anonymized statistics about how you use its functionality. We kindly ask you to opt in to these statistics!

This anonymous data greatly helps us understand our users better, see what works, what is causing difficulties, and where we should direct our focus. To enable statistics, go to Preferences, open Appearance & Behaviour | System Settings | Data Sharing and activate the Send usage statistics checkbox.

Top issue reporters since Kotlin 1.3

We’d like to thank all the members of the community who helped us make this release better by reporting issues to YouTrack! We’ve made a list of the top 20 reporters and would like to thank them specifically:

Igor Wojda (145 issues); Louis CAD (87 issues); Marc Knaup (86 issues); AndroidDeveloperLB (83 issues); Robert Stoll (68 issues); Morgan Bartholomew (62 issues); Victor Turansky (54 issues); Guan Tianyi (51 issues); Scott Pierce (38 issues); Andreas Malik (37 issues); Steven Schäfer (37 issues); Björn Kautler (36 issues); Róbert Papp (34 issues); Toshiaki Kameyama (30 issues); Nicholas Bilyk (29 issues); Michael Bailey (26 issues); Jake Wharton (25 issues); Lamberto Basti (24 issues); Serge Pro (23 issues); Egor Andreevici (21 issues).

Start using Kotlin 1.4 right now

As always, you can try Kotlin online at

In Gradle and Maven, use 1.4.0 as the compiler version. See the docs for Gradle and for Maven.

IntelliJ IDEA and Android Studio automatically prompt you to update the Kotlin plugin to version 1.4.0. You can also open Preferences | Plugins and update the Kotlin plugin manually.

The command-line compiler can be downloaded from the GitHub release page.

You can use the following versions of the libraries published together with this release:

The versions of libraries from




etc.) can be found in the corresponding repository.

The latest IDE performance improvements, including the code highlighting speed-up, require IntelliJ IDEA 2020.1+ and Android Studio 4.1+.

If you run into any problems with the new release, you can find help on Slack (get an invite here) and report issues in our YouTrack.

Thank you!

We’re really grateful to everyone who has tried out and given us feedback on the Kotlin EAPs and experimental features. We are developing the Kotlin language together with you, and making many design decisions based on your invaluable input. Keeping this fast and effective feedback loop going with the community is really important to help Kotlin become the best it can be!

We want to say a big thank you to all our external contributors whose pull requests were included in this release. You helped us make this release happen!

We’re grateful to all members of our community who are creating so many amazing things with Kotlin. Kotlin 1.4: One for all!

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