There's a lot of good stuff in this release but the most pressing order of business is a patch that fixes a consensus bug in OP_CAT that caused bchd to choke on block 577669. If your node is stuck after installing this version you'll need to run the following command to get the chain moving again:
bchctl reconsiderblock 0000000000000000001df2299a0d705bc95df7045398a32d1dea5ccff7bb9fb6
Other features in this release include:
- Bip152 Compact Block Relay
- Use cached hashes when validating scripts. This reduces the number of hashes that are calculated for multi-input transactions. Should result in a nice validation speed up.
- We've made a decision to revert to the original block filter format using outpoints instead of input-scriptpubkeys. The Bitcoin Core developers made the change to the spec but it pretty dramatically reduces lite client security with very little upside. So we are reverting back to the original format. This requires migrating the cfilter index to the new format. On the first start after upgrading it will run the migration, which will take about a half hour.