# Pending

BREAKING CHANGES:

* CLI/RPC/Config
  - [config] \#2169 Replace MaxNumPeers with MaxNumInboundPeers and MaxNumOutboundPeers
  - [config] \#2300 Reduce default mempool size from 100k to 5k, until ABCI rechecking is implemented.
  - [rpc] \#1815 `/commit` returns a `signed_header` field instead of everything being top-level

* Apps
  - [abci] Added address of the original proposer of the block to Header
  - [abci] Change ABCI Header to match Tendermint exactly
  - [abci] \#2159 Update use of `Validator` (see
    [ADR-018](https://github.com/tendermint/tendermint/blob/develop/docs/architecture/adr-018-ABCI-Validators.md)):
    - Remove PubKey from `Validator` (so it's just Address and Power)
    - Introduce `ValidatorUpdate` (with just PubKey and Power)
    - InitChain and EndBlock use ValidatorUpdate
    - Update field names and types in BeginBlock
  - [state] \#1815 Validator set changes are now delayed by one block
    - updates returned in ResponseEndBlock for block H will be included in RequestBeginBlock for block H+2

* Go API
  - [lite] \#1815 Complete refactor of the package
  - [node] \#2212 NewNode now accepts a `*p2p.NodeKey`
  - [libs/common] \#2199 Remove Fmt, in favor of fmt.Sprintf
  - [libs/common] SplitAndTrim was deleted
  - [libs/clist] Panics if list extends beyond MaxLength
  - [crypto] \#2205 Rename AminoRoute variables to no longer be prefixed by signature type.

* Blockchain Protocol
  - [state] \#1815 Validator set changes are now delayed by one block (!)
    - Add NextValidatorSet to State, changes on-disk representation of state
  - [state] \#2184 Enforce ConsensusParams.BlockSize.MaxBytes (See
    [ADR-020](https://github.com/tendermint/tendermint/blob/develop/docs/architecture/adr-020-block-size.md)).
    - Remove ConsensusParams.BlockSize.MaxTxs
    - Introduce maximum sizes for all components of a block, including ChainID
  - [types] Updates to the block Header:
    - \#1815 NextValidatorsHash - hash of the validator set for the next block,
      so the current validators actually sign over the hash for the new
      validators
    - \#2106 ProposerAddress - address of the block's original proposer
  - [consensus] \#2203 Implement BFT time
    - Timestamp in block must be monotonic and equal the median of timestamps in block's LastCommit
  - [crypto] \#2239 Secp256k1 signature changes (See
    [ADR-014](https://github.com/tendermint/tendermint/blob/develop/docs/architecture/adr-014-secp-malleability.md)):
    - format changed from DER to `r || s`, both little endian encoded as 32 bytes.
    - malleability removed by requiring `s` to be in canonical form.

* P2P Protocol
  - [p2p] \#2263 Update secret connection to use a little endian encoded nonce
  - [blockchain] \#2213 Fix Amino routes for blockchain reactor messages


FEATURES:
- [types] \#2015 Allow genesis file to have 0 validators
  - Initial validator set can be determined by the app in ResponseInitChain
- [rpc] \#2161 New event `ValidatorSetUpdates` for when the validator set changes
- [crypto/multisig] \#2164 Introduce multisig pubkey and signature format
- [libs/db] \#2293 Allow passing options through when creating instances of leveldb dbs

IMPROVEMENTS:
- [docs] Lint documentation with `write-good` and `stop-words`.
- [scripts] Added json2wal tool, which is supposed to help our users restore
  corrupted WAL files and compose test WAL files (@bradyjoestar)
- [mempool] \#2234 Now stores txs by hash inside of the cache, to mitigate memory leakage

BUG FIXES:
- [config] \#2284 Replace `db_path` with `db_dir` from automatically generated configuration files.
- [mempool] \#2188 Fix OOM issue from cache map and list getting out of sync
- [state] \#2051 KV store index supports searching by `tx.height`
- [rpc] \#2327 `/dial_peers` does not try to dial existing peers
- [node] \#2323 Filter empty strings from config lists
- [abci/client] \#2236 Fix closing GRPC connection