Polkadot v0.9.12

Upgrade priority: Medium (timely upgrade recommended) due to changes: Use correct db path for parity-db (paritytech/substrate#9971), ✅ audited Rework Transaction Priority calculation (paritytech/substrate#9834), Introduce block authorship soft deadline (paritytech/substrate#9663)

Native runtimes:

• Polkadot: 9120
• Kusama: 9120
• Westend: 9120

This release was tested against the following versions of rustc. Other versions may work.

• rustc 1.55.0 (c8dfcfe04 2021-09-06)
• rustc 1.57.0-nightly (51e514c0f 2021-09-12)

WASM runtimes built with srtool v0.9.17 using rustc 1.53.0 (53cb7b09b 2021-06-17).

Proposal hashes:

• polkadot_runtime-v9120.compact.compressed.wasm: 0x59589d32b92a1ed552c14f099e54afb65b3a64d28084963ff1072336569aa395
• kusama_runtime-v9120.compact.compressed.wasm: 0x66f63d87c2e90994684122d97155a102af4310a4e9d47026005efea2acecfd1f

Changes

• Create a README for XCMv1 detailing notable changes (#4058)
• validator-discovery: don't remove multiaddr of requested PeerIds (#4036)

Client

• make the ws buffer size configurable (paritytech/substrate#10013)
• sc-executor-wasmtime: upgrade wasmtime to 0.30.0 (paritytech/substrate#10003)
• Use correct db path for parity-db (paritytech/substrate#9971)
• Disable log reloading by default (paritytech/substrate#9966)
• --dev implies --tmp (paritytech/substrate#9938)
• Quickly skip invalid transactions during block authorship. (paritytech/substrate#9789)
• Introduce block authorship soft deadline (paritytech/substrate#9663)

Runtime

• ✅ not live Dispatchable XCMs should translate to v0 (#4062)
• ✅ not live Tidy up XCM errors in preparation for v2. (#3988)
• ✅ audited Allow an Offset to Lease Periods (#3980)
• ✅ trivial More lenient mechanism for identifying stash accounts in purge_keys (paritytech/substrate#10004)
• ⏳ pending non-critical audit Root origin always bypass all filter, other origin cannot bypass BaseCallFilter even when constructed from Root origin (paritytech/substrate#9948)
• ✅ audited Rework Transaction Priority calculation (paritytech/substrate#9834)