v6.0.0-alpha.4

Version 6.0.0-alpha.4

Here's how you can use this release:

cargo install --force --locked --git https://github.com/use-ink/cargo-contract --tag v6.0.0-alpha.4

ink = { git = "https://github.com/use-ink/ink.git", tag = "v6.0.0-alpha.4", default-features = false, features = ["unstable-hostfn"] }
ink_e2e = { git = "https://github.com/use-ink/ink.git", tag = "v6.0.0-alpha.4", default-features = false }

You also need to install the latest ink-node release (there are binaries available for this release!).

Compatibility:

• Rust >= 1.88
• cargo-contract v6.0.0-alpha.4
• ink-node v0.45.1
• polkadot-sdk from use-ink/polkadot-sdk/a71ec19a94702ea71767ba5ac97603ea6c6305c1
• Passet Hub (was upgraded on Sep 12, 2025)

We have to use a slight fork of polkadot-sdk for the moment. It's just polkadot-sdk/master plus two
commits on top with pre-compiles. Those two commits are PRs to polkadot-sdk that haven't been merged yet, but should be any day now.

Added

• Add integration test for arithmetic overflow checks - #2631
• E2E: Misc quality of life improvements, new API functions, better debuggability ‒ 2634

Changed

• Error on message and constructor selector overrides in Solidity ABI mode - #2638
• Improve abstractions for Solidity ABI encoding Result types - #2635
• Feature gate xcm - #2641
• Refactor multi ABI interfaces for event emission via ink_env - #2643

Fixed

• Bring intended panic handler behavior back ‒ 2636
• Support name attribute in trait definitions - #2644