Kotlin 2.1.20 made K2 kapt the default and updated the Lombok plugin, while adding DWARF debug information and custom formatters for Kotlin/Wasm development builds. These changes improve specific tools; they do not mean that every third-party compiler plugin is compatible with K2. Later, Kotlin 2.2.20 made Kotlin/Wasm Beta and simplified browser debugging through Gradle development-run tasks.
What changed for K2 compiler plugins?
Kotlin 2.1.20, released March 20, 2025, made the K2 implementation of kapt the default. Teams that ran into problems could temporarily opt out by setting kapt.use.k2=false. The same release updated the Kotlin Lombok plugin, adding @SuperBuilder support and improving @Builder, including its use with constructors. See the Kotlin 2.1.20 release notes.
These are named changes to kapt and Lombok—not a declaration that the wider third-party plugin ecosystem works with K2. Kotlin’s compiler-plugin documentation describes the API as low-level and very unstable: there is no stable API guarantee, and a plugin built for one compiler version is not guaranteed to work with another. Plugin authors may need to build against the compiler version used by a project or publish plugin versions for the compiler versions they support. Where they meet the need, Kotlin suggests considering KSP or external linters instead. See the Kotlin compiler plugin documentation.
How do I debug Kotlin/Wasm in a browser?
Kotlin 2.2.20, released September 10, 2025, made Kotlin/Wasm Beta and added browser debugging support to Gradle’s *DevRun tasks. The tasks serve project sources so a modern browser can use them for breakpoints, variable inspection, and stepping, without the manual source-serving setup earlier projects may have needed. If you already configured source serving yourself, remove that configuration to avoid conflicts. The Kotlin 2.2.20 release notes also warn that source-serving changes may cause repeated reloads before compilation and bundling finish; teams may need to adjust webpack configuration.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Keep source-serving tasks local
Because these tasks serve source files, use them for local development, not cloud or production environments where those files might be exposed. Kotlin’s 2.2.20 guidance makes that distinction explicit.
When is DWARF debugging useful?
Kotlin 2.1.20 added the compiler option -Xwasm-generate-dwarf, which places DWARF debug information in generated Wasm binaries. This route is aimed especially at debugging Kotlin/Wasm applications in standalone Wasm virtual machines. It works only when both the VM and the debugger support DWARF.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
The release also enabled custom formatters by default for development builds, which can make values easier to inspect. The browser’s developer tools must allow custom formatters for them to work. These Wasm changes are documented in the Kotlin 2.1.20 release notes.
| Debugging route | How it works | Best fit and constraint |
|---|---|---|
| Browser development debugging | Gradle *DevRun tasks serve project sources; the browser supports breakpoints, variable inspection, and stepping. |
Convenient for local development. Avoid cloud and production environments because sources may be exposed. |
| DWARF-based debugging | The compiler embeds DWARF data in the Wasm binary with -Xwasm-generate-dwarf. |
Useful with a standalone Wasm VM and debugger that both support DWARF. |
What happened in later Kotlin releases?
The 2.1.20 and 2.2.20 changes are part of a sequence of updates, not a single ecosystem-wide compatibility switch.
The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
| Release | Date | Relevant update |
|---|---|---|
| Kotlin 2.1.20 | March 20, 2025 | K2 kapt became the default; Lombok gained @SuperBuilder support and an improved @Builder; Kotlin/Wasm gained DWARF output and development-build custom formatters. |
| Kotlin 2.2.20 | September 10, 2025 | Kotlin/Wasm became Beta; Gradle *DevRun tasks added source serving for browser debugging. |
| Kotlin 2.3.0 | December 16, 2025 | Fully qualified names and a new exception-handling proposal became defaults for relevant targets; Latin-1 string storage was compacted. |
| Kotlin 2.3.20 | March 16, 2026 | Lombok was listed as Alpha, with improved JPA support highlighted; the documentation says it remained under development. |
The later Wasm size figures have specific comparisons: Kotlin 2.3.0 release notes report up to 13% smaller binaries from Latin-1 storage optimization compared with builds without that optimization, based on experiments on JetBrains’ KotlinConf application. The same notes report up to 8% smaller binaries when fully qualified names are enabled, compared with earlier versions that did not store them. These are reported maxima under those stated comparisons, not guarantees for every project. See the Kotlin 2.3.0 release notes. For the later Lombok status, see the Kotlin 2.3.20 release notes.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
