Runtime

• Custom Codec Implenetation for NPoS Election (#6720)
• Successful note_imminent_preimage is free (#6793)
• pallet-democracy use of weightinfo (#6783)
• Update Balances Pallet to use WeightInfo (#6610)
• pallet-evm: add builtin support for the four basic Ethereum precompiles (#6743)
• Allow PostDispatchInfo to disable fees (#6749)
• pallet-evm: add support for tuple-based precompile declarations (#6681)
• grandpa: allow noting that the set has stalled (#6725)

Client

• Merge Subkey into sc-cli (#4954)
• RpcHandlers Refactorings (#6846)
• client/authority-discovery: Introduce AuthorityDiscoveryService (#6760)
• Implement tracing::Event handling & parent_id for spans and events (#6672)
• Move to upstream wasmtime, refactor globals snapshot (#6759)
• Revalidate transactions only on latest best block (#6824)
• Allow task manager to have children (#6771)
• client/network: Expose DHT query duration to Prometheus (#6784)
• client/network: Add peers to DHT only if protocols match (#6549)
• Name all the tasks! (#6726)
• Child nodes can be handled by adding a child TaskManager to the parent's TaskManager (#6771)

API

• pow: add access to pre-digest for algorithm verifiers (#6900)
• babe, aura, pow: only call check_inherents if authoring version is compatible (#6862)
• Implement 'transactional' annotation for runtime functions. (#6763)
• seal: Change prefix and module name from "ext_" to "seal_" for contract callable functions (#6798)
• Add Subscription RPC for Grandpa Finality (#5732)
• seal: Fix and improve error reporting (#6773)
• Allow blacklisting blocks from being finalized again after block revert (#6301)
• BABE slot and epoch event notifications (#6563)
• Add memory-tracker feature to sp-trie to fix wasm panic (#6745)