• Breaking change (TypeScript only) The *.d.ts files now contain TypeScript 3.8 features (specifically #private), which is not usable in TS versions < 3.8
• Breaking change - api.derive.staking.* has updated result types and detects support for lazy payouts queries
• Rework type generation for api.{query, tx} to properly handle complex type inputs (Thanks to https://github.com/monitz87)
• Rework metadata --strict mode to effectively decorate chain metadata (Thanks to https://github.com/monitz87)
• Add api.rpc.chain.subscribeAllHeads (not just best) (Thanks to https://github.com/jak-pan)
• Add api.rpc.engine.* for manual seal support
• Add api.injectMetadata(metadata) to initialize API with a specific metadata version
• The api now checks for runtime upgrades, augmenting the interfaces with new metadata when found
• Support types & interfaces required for lazy reaping, lazy payouts & offchain phragmen
• Option types now has an .unwrapOrDefault as an complement to .unwrap & .unwrapOr
• Support JS BigInt inputs in any derived UInt and Int object, e.g. api.tx.balances.transfer(..., 9876543210123456789n)
• UInt & Int now does source bitLength checks upon construction
• Registry now exposes .createType(<type>, ...args) as an additional helper (like the API)
• Expand .toHuman on ExtrinsicEra, SubmittableResult & Vote
• Move DigestItem, Fixed64, H160, H256 & H512 to interfaces in @polkadot/types/interfaces
• Align construction of unknown types in registry.get consistently warn on detection, throw on use
• Support for arbitrary u* types via UInt<bitLength> type definitions
• Expose static .with on UInt, Int & U8aFixed classes with optional type name override
• Remove 11 Jan 2019 extrinsic length hack
• Use ES #field on private class fields as applicable
• Move types/primitive/{extrinsics, generic} to types/{extrinsics, generic}
• Cleanup augmentation and generation scripts for type definitions, aligning with api augmentation
• Bump to @polkadot/{util, util-crypto, keyring} 2.5.1