Cuspidation

New features:

• Prometheus support for monitoring (#441)
• neo-go contract invoke now accepts endpoint parameter (--endpoint or
  -e) to specify RPC node to be used for invocation (#363)
• RPC server now supports invokescript method (#348)
• minimum peers number can now be configured (#468)
• configured CORS workaround implemented in the RPC package (#469)

Behavior changes:

• neo-go contract inspect now expects avm files in input, but can also
  compile Go code with -c parameter (previously is was done by default),
  inspect subcommand was removed from neo-go vm (it dumped avm files in
  previous release) (#463)
• the default minimum peers was reduced to 3 for privnet setups to avoid
  useless reconnections to only 4 available nodes
• RPC service now has its own section in configuration, update your
  configurations (#469)

Improvements:

• VM.Load() now clears the state properly, making VM reusable after the Run()
  (#463)
• Compile() in compiler package no longer accepts Options, they were not used
  previously anyway (#463)
• invocation stack depth is now limited in the VM (#461)
• VM got new State() method to get textual state description (#463)
• vm's Stack structure can now be marshalled into JSON (#463)

Bugs fixed:

• race in discoverer part of the server (#445)
• RPC server giving improper (not JSON) respons to unimplemented API requests
  (#463)

Cribration

Release 0.60.0 brings with it an implementation of all NEO 2.0 VM opcodes,
full support for transaction relaying, improved logging, a bunch of fixes and
an updated project logo.

New features:

• blocks dumping from DB to file and restoring from file to DB (#436)
• new logo (#444)
• implemented getdata message handling (#448)
• issue tx processing (#450)
• CALL_I, CALL_E, CALL_ET, CALL_ED, CALL_EDT implementation in the VM (#192)

Internal improvements:

• codestyle fixes (#439, #443)
• removed spurious prints from all the code, now everything is passed/logged
  correctly (#247)

Bugs fixed:

• missing max size limitation in CAT and PUSHDATA4 opcodes implementation
  (#435)
• wrong interpretation of missing unspent coin state when checking for double
  spend (#439)
• panic on successive node starts when no headers were saved in the DB (#440)
• NEWARRAY/NEWSTRUCT opcodes didn't copy operands for array<->struct
  conversions
• deadlock in MemPool on addition (#448)
• transactions were not removed from the MemPool when processing new signed
  block (#446)
• wrong contract property constants leading to storage usage failures (#450)

Confirmation

With over a 100 commits made since 0.50.0 release 0.51.0 brings with it full
block verification, improved and fixed transaction verifications,
implementation of most of interop functions and VM improvements. Block
verification is an important milestone on the road to full consensus node
support and it required implementing a lot of other associated functionality.

New features:

• CHECKSIG, VERIFY and CHECKMULTISIG instructions in VM (#269)
• witness verification logic for transactions (#368)
• NEWMAP, HASKEY, KEYS and VALUES instructions, support for Map type in
  PICKITEM, SETITEM, REMOVE, EQUAL, ARRAYSIZE (#359)
• configurable transaction verification on block addition (#415, #418)
• contract storage and support for VM to call contracts via APPCALL/TAILCALL
  (#417)
• support for Interop type in VM (#417)
• VM now has stepInto/stepOver/stepOut method implementations for debugging
  matching neo-vm behavior (#187)
• storage support for contracts (#418)
• added around 90% of interop functions (#418)
• Invocation TX processing now really does invoke contracts using internal VM
  (#418)
• blocks are now completely verified when added to the chain (if not
  configured otherwise; #12, #418)

Behavior changes:

• full block verification is now enabled for all network types
• block's transaction verification enabled for privnet setups, mainnet and
  testnet don't have it enabled

Technical improvements:

• GetVarIntSize and GetVarStringSize were removed from the io package (use
  GetVarSize instead; #408)
• OVER implementation was optimized to not pop the top element from the stack
  (#406, part of #196 work)
• vm.VM was extended with HasFailed() method to check its state (previously
  external VM users couldn't do it; #411)
• redesigned input block queue mechanism, now it's completely moved out of
  the Blockchain, which only accepts the next block via AddBlock() (#414)
• unpersisted blocks are now fully available with the Blockchain (thus we
  have symmetry now in AddBlock/GetBlock APIs; #414, #366)
• removed duplicating batch structures from BoltDB and Redis code, now all of
  them use the same batch as MemoryStore does (#414)
• MemoryStore was exporting its mutex for no good reason, now it's hidden
  (#414)
• storage layer now returns ErrKeyNotFound for all DBs in appropriate
  situations (#414)
• VM's PopResult() now doesn't panic if there is no result (#417)
• VM's Element now has a Value() method to quickly get the item value (#417)
• VM's stack PushVal() method now accepts uint8/16/32/64 (#417, #418)
• VM's Element now has TryBool() method similar to Bool(), but without a
  panic (for external VM users; #417)
• VM has now completely separated instruction read and execution phases
  (#417)
• Store interface now has Delete method (#418)
• Store tests were reimplemented to use one test set for all Store
  implementations, including LevelDB that was not tested at all previously
  (#418)
• Batch interface doesn't have Len method now as it's not used at all (#418)
• NewFromRawBytes functions were renamed to NewFromASN1 in the keys
  package, previous naming made it easy to confuse them with functions
  operating with NEO serialization format (#418)
• PublicKey's IsInfinity method is exported now (#418)
• smartcontract package now has CreateSignatureRedeemScript() matching C#
  code (#418)
• vm package now has helper functions
  IsSignatureContract/IsMultiSigContract/IsStandardContract matching C# code
  (#418)
• Blockchain's GetBlock() now returns full block with transactions (#418)
• Block's Verify() was changed to return specific error (#418)
• Blockchain's GetTransationResults was renamed into GetTransactionResults
  (#418)
• Blockchainer interface was extended with GetUnspentCoinState,
  GetContractState and GetScriptHashesForVerifying methods (#418)
• introduced generic MemCacheStore that is used now for write caching
  (including temporary stores for transaction processing) and batched
  persistence (#425)

Bugs fixed:

• useless persistence failure message printed with no error (#409)
• persistence error message being printed twice (#409)
• segmentation fault upon receival of message that is not currently handled
  properly (like "consensus" message; #409)
• BoltDB's Put for a batch wasn't copying data which could lead to data
  corruption (#409)
• APPEND instruction applied to struct element was not copying it like neo-vm
  does (#405, part of #196 work)
• EQUAL instruction was comparing array contents, while it should've compared
  references (#405, part of #196 work)
• SUBSTR instruction was failing for out of bounds length parameters while it
  should've truncated them to string length (#406, part of #196 work)
• SHL and SHR implementations had no limits, neo-vm restricts them to
  -256/+256 (#406, part of #196 work)
• minor VM state mismatches with neo-vm on failures (#405, #406)
• deadlock on Blockchain init when headers pointer is not in sync with the
  hashes list (#414)
• node failed to request blocks when headers list was exactly one position
  ahead of block count (#414)
• TestRPC/getassetstate_positive failed occasionally (#410)
• panic on block verification with no transactions inside (#415)
• DutyFlag check in GetScriptHashesForVerifying was not done correctly (#415)
• default asset expiration for assets created with Register TX was wrong, now
  it matches C# code (#415)
• Claim transactions needed specific GetScriptHashesForVerifying logic to
  be verified correctly (#415)
• VerifyWitnesses wasn't properly sorting hashes and witnesses (#415)
• transactions referring to two outputs of some other transaction were
  failing to verify (#415)
• wrong program dumps (#295)
• potential data race in logging code (#418)
• bogus port check during handshake (#432)
• missing max size checks in NEWARRAY, NEWSTRUCT, APPEND, PACK, SETITEM
  (#427, part of #373)

Consolidation

The first release from the new team focuses on bringing all related
development effort into one codebase, refactoring things, fixing some
long-standing bugs and adding new functionality. This release merges two
radically different development branches --- dev and master that were
present in the project (along with all associated pull requests) and also
brings in changes made to the compiler in the neo-storm project.

New features:

• configurable storage backends supporting LevelDB, in-memory DB (for
  testing) and Redis
• BoltDB support for storage backend
• updated and extended interop APIs (thanks to neo-storm)

Notable behavior changes:

• the default configuration for privnet was changed to use ports 20331 and
  20332 so that it doesn't clash with the default dockerized neo-privnet
  setups
• the default configuration path was changed from ../config to ./config,
  at this stage it makes life a bit easier for development, later this will
  be changed to some sane default for production version
• VM CLI now supports type inference for run parameters (you don't need to
  specify types explicitly in most of the cases) and treats operation
  parameter as mandatory if anything is passed to run

VM improvements:

• added implementation for EQUAL, NZ, PICK, TUCK, XDROP, INVERT,
  CAT, SUBSTR, LEFT, RIGHT, UNPACK, REVERSE, REMOVE
• expanded tests
• better error messages for different erroneous code
• implemented item conversions following neo-vm behavior: array to/from
  struct, bigint to/from boolean, anything to bytearray and anything to
  boolean
• improved compatibility with neo-vm (#394)

Technical improvements:

• switched to Go 1.12+
• gofmt, golint (#213)
• fixed and improved CircleCI builds
• removed internal rfc6969 package (#285)
• refactored util/crypto/io packages, removed a lot of duplicating code
• updated READMEs and user-level documents
• update Makefile with useful targets
• dropped internal base58 implementation (#355)
• updated default seed lists for mainnet and testnet from neo-cli

Bugs fixed:

• a lot of compiler fixes from neo-storm
• data access race in memory-backed storage backend (#313)
• wrong comparison opcode emitted by compiler (#294)
• decoding error in publish transactions (#179)
• decoding error in invocation transactions (#173)
• panic in state transaction decoding
• double VM run from CLI (#96)
• non-constant time crypto (#245)
• APPEND pushed value on the stack and worked for bytearrays (#391)
• reading overlapping hash blocks from the DB leading to blockchain state
  neo-go couldn't recover from (#393)
• codegen for append() wasn't type-aware and emitted wrong code (#395)
• node wasn't trying to reconnect to other node if connection failed (#390)
• stricly follow handshare procedure (#396)
• leaked connections if disconnect happened before handshake completed (#396)