- [blockchain] [\#3561](https://github.com/tendermint/tendermint/issues/3561) Add early version of the new blockchain reactor, which is supposed to be more modular and testable compared to the old version. To try it, you'll have to change `version` in the config file, [here](https://github.com/tendermint/tendermint/blob/master/config/toml.go#L303) NOTE: It's not ready for a production yet. For further information, see [ADR-40](https://github.com/tendermint/tendermint/blob/master/docs/architecture/adr-040-blockchain-reactor-refactor.md) & [ADR-43](https://github.com/tendermint/tendermint/blob/master/docs/architecture/adr-043-blockchain-riri-org.md)
- [mempool] [\#3826](https://github.com/tendermint/tendermint/issues/3826) Make `max_msg_bytes` configurable(@bluele)
- [node] [\#3846](https://github.com/tendermint/tendermint/pull/3846) Allow replacing existing p2p.Reactor(s) using [`CustomReactors`
- [p2p] [\#3834](https://github.com/tendermint/tendermint/issues/3834) Do not write 'Couldn't connect to any seeds' error log if there are no seeds in config file
- [rpc] [\#3818](https://github.com/tendermint/tendermint/issues/3818) Make `max_body_bytes` and `max_header_bytes` configurable(@bluele)
- [mempool] [\#3826](https://github.com/tendermint/tendermint/issues/3826) Make `max_msg_bytes` configurable(@bluele)
- [blockchain] [\#3561](https://github.com/tendermint/tendermint/issues/3561) Add early version of the new blockchain reactor, which is supposed to be more modular and testable compared to the old version. To try it, you'll have to change `version` in the config file, [here](https://github.com/tendermint/tendermint/blob/master/config/toml.go#L303) NOTE: It's not ready for a production yet. For further information, see [ADR-40](https://github.com/tendermint/tendermint/blob/master/docs/architecture/adr-040-blockchain-reactor-refactor.md) & [ADR-43](https://github.com/tendermint/tendermint/blob/master/docs/architecture/adr-043-blockchain-riri-org.md)
- [rpc] [\#2252](https://github.com/tendermint/tendermint/issues/2252) Add `/broadcast_evidence` endpoint to submit double signing and other types of evidence
### IMPROVEMENTS:
- [abci] [\#3809](https://github.com/tendermint/tendermint/issues/3809) Recover from application panics in `server/socket_server.go` to allow socket cleanup (@ruseinov)
- [rpc] [\#2252](https://github.com/tendermint/tendermint/issues/2252) Add `/broadcast_evidence` endpoint to submit double signing and other types of evidence
- [p2p] [\#3664](https://github.com/tendermint/tendermint/issues/3664) p2p/conn: reuse buffer when write/read from secret connection(@guagualvcha)
- [p2p] [\#3834](https://github.com/tendermint/tendermint/issues/3834) Do not write 'Couldn't connect to any seeds' error log if there are no seeds in config file