I compiled a dozen Kotlin sugars and read the javap output. Three tiers: ?. is a real ifnull jump with zero allocation, inline saves 0.01 B per call while copying the body, string templates hinge on jvmTarget, and lazy’s three modes I could not measure.
Kotlin 2.5.0-RC pushes full value classes, so I read bytecode: javap shows a plain class, no box-impl. In a list it allocates 36.0 B, the same as the data class. The real win is a class file 21% smaller, and default destructuring still silently swaps names.
34 lines of C bound twice, through Flutter’s ffigen and KMP’s cinterop. Under AOT both call in near 0.1us. KMP’s debug build made struct returns 30x slower until release fixed it. Five pitfalls each, led by a version wall and a silently empty binding file.
Stroke(join = Round) was drawn as Miter on Compose Multiplatform’s desktop, iOS and web targets while Android stayed fine. The root cause is a setter that never runs. I rendered both versions and diffed them pixel by pixel: 1,619 pixels apart.
Jake Wharton runs Compose on the server with Molecule, renders HTML with kotlinx.html, pushes it over SSE, and merges it with Idiomorph. I rebuilt it and found that whether your text input survives comes down to three defaults.
Compose code on both sides, but Tencent picked native rendering over Skia: six platforms, four renderers, 155,000 lines of platform glue.
1.13 has one new feature and a pile of fixes. The heavy part shipped two months earlier, when hot reload got an MCP server.
On September 10, Shopify’s head of mobile published a post.
On October 21, Kotlin 2.5.0-Beta2 shipped. Most people open the notes, read the four promoted and two experimental language features, decide it is unremarkable, and close the tab.
On October 6, JetBrains’ Amper blog published its final post, titled Amper Is Now the Kotlin Toolchain. The name carries a line underneath, Moving to the Kotlin Blog, and it means what it says: that blog stops updating as of that day and merges into the Kotlin blog.
On October 5 JetBrains published a short announcement with a blunt title: IDE support for the Swift language is ending in the KMP plugin. The effective versions are specific: IntelliJ IDEA 2026.3 and Android Studio Rabbit 2 | 2026.2.2.
If you write Kotlin Multiplatform you have probably hit this: the line is red in the IDE, underlined with a cannot find symbol, you hesitate for ages and do not dare commit, then you build and it is green, and it even runs correctly.