- [txindex] [\#4466](https://github.com/tendermint/tendermint/pull/4466) Allow to index an event at runtime (@favadi)
- [evidence] [\#4722](https://github.com/tendermint/tendermint/pull/4722) Improved evidence db (@cmwaters)
- [buildsystem] [\#4378](https://github.com/tendermint/tendermint/pull/4738) Replace build_c and install_c with TENDERMINT_BUILD_OPTIONS parsing. The following options are available:
- nostrip: don't strip debugging symbols nor DWARF tables.
- cleveldb: use cleveldb as db backend instead of goleveldb.
- race: pass -race to go build and enable data race detection.
### BUG FIXES:
- [light] [\#4741](https://github.com/tendermint/tendermint/pull/4741) Correctly return `ErrSignedHeaderNotFound` and `ErrValidatorSetNotFound` on corresponding RPC errors (@erikgrinaker)