The is a stability and soft forking build.
There are two changes in particular that witnesses should upgrade for. These are both related to security of the blockchain and/or security of individual nodes.
- A new bandwidth algorithm has been implemented that more accurately saves bandwidth used over time and prevents abuse by sending two transactions in the same block. Along with this change, the soft fork that was preventing two transactions from the same account from being present in a block has been lifted.
- Fixed asset deserialization error that could result in a div0 DoS.
The rest are optimizations or non-forking bug fixes.
- Blocks are no longer saved in the memory mapped file once written to the block log.
- Various stability improvements in the block log and fork database.
- Nodes now require their peers to report a Chain ID and will actively reject connections that don't. All nodes running 0.16.0 report their Chain ID.
- steemd now periodically reports how much free memory in the memory mapped file remains.
- The Database API now has a method,
get_ops_in_blockwhich returns all operations contained in a block. Full account history must be enabled for all operations to be returned.
- Custom operations that have only a required posting authority show up in account history.
- The Equihash PoW will no longer display egregious error messages in the
account_by_keyplugin and accounts created through Equihash mining will be able to be looked up by key in the CLI Wallet.
- The author reward virtual op will display the entirety of the comment's permlink.
- Properties contained in the witness schedule object are properly mirrored when contained in other objects.
- Tag filtering has been improved and much of the display logic has been moved to Steemit.com