tendermint/UPGRADING.md

Upgrading Tendermint Core

This guide provides steps to be followed when you upgrade your applications to a newer version of Tendermint Core.

v0.26.0

New 0.26.0 release contains a lot of changes to core data types and protocols. It is not compatible to the old versions and there is no straight forward way to update old data to be compatible with the new version.

To reset the state do:

$ tendermint unsafe_reset_all

Here we summarize some other notable changes to be mindful of.

Config Changes

All timeouts must be changed from integers to strings with their duration, for instance flush_throttle_timeout = 100 would be changed to flush_throttle_timeout = "100ms" and timeout_propose = 3000 would be changed to timeout_propose = "3s".

RPC Changes

The default behaviour of /abci_query has been changed to not return a proof, and the name of the parameter that controls this has been changed from trusted to prove. To get proofs with your queries, ensure you set prove=true.

Various version fields like amino_version, p2p_version, consensus_version, and rpc_version have been removed from the node_info.other and are consolidated under the tendermint semantic version (ie. node_info.version) and the new block and p2p protocol versions under node_info.protocol_version.

ABCI Changes

Field numbers were bumped in the Header and ResponseInfo messages to make room for new version fields. It should be straight forward to recompile the protobuf file for these changes.

Proofs

The ResponseQuery.Proof field is now structured as a []ProofOp to support generalized Merkle tree constructions where the leaves of one Merkle tree are the root of another. If you don't need this functionality, and you used to return <proof bytes> here, you should instead return a single ProofOp with just the Data field set:

[]ProofOp{
    ProofOp{
        Data: <proof bytes>,
    }
}

For more information, see:

• ADR-026
• Relevant ABCI documentation
• Description of keys

Go API Changes

crypto.merkle

The merkle.Hasher interface was removed. Functions which used to take Hasher now simply take []byte. This means that any objects being Merklized should be serialized before they are passed in.

node

The node.RunForever function was removed. Signal handling and running forever should instead be explicitly configured by the caller. See how we do it here.

Other

All hashes, except for public key addresses, are now 32-bytes.

v0.25.0

This release has minimal impact.

If you use GasWanted in ABCI and want to enforce it, set the MaxGas in the genesis file (default is no max).

v0.24.0

New 0.24.0 release contains a lot of changes to the state and types. It's not compatible to the old versions and there is no straight forward way to update old data to be compatible with the new version.

To reset the state do:

$ tendermint unsafe_reset_all

Here we summarize some other notable changes to be mindful of.

Config changes

p2p.max_num_peers was removed in favor of p2p.max_num_inbound_peers and p2p.max_num_outbound_peers.

# Maximum number of inbound peers
max_num_inbound_peers = 40

# Maximum number of outbound peers to connect to, excluding persistent peers
max_num_outbound_peers = 10

As you can see, the default ratio of inbound/outbound peers is 4/1. The reason is we want it to be easier for new nodes to connect to the network. You can tweak these parameters to alter the network topology.

RPC Changes

The result of /commit used to contain header and commit fields at the top level. These are now contained under the signed_header field.

ABCI Changes

The header has been upgraded and contains new fields, but none of the existing fields were changed, except their order.

The Validator type was split into two, one containing an Address and one containing a PubKey. When processing RequestBeginBlock, use the Validator type, which contains just the Address. When returning ResponseEndBlock, use the ValidatorUpdate type, which contains just the PubKey.

Validator Set Updates

Validator set updates returned in ResponseEndBlock for height H used to take effect immediately at height H+1. Now they will be delayed one block, to take effect at height H+2. Note this means that the change will be seen by the ABCI app in the RequestBeginBlock.LastCommitInfo at block H+3. Apps were already required to maintain a map from validator addresses to pubkeys since v0.23 (when pubkeys were removed from RequestBeginBlock), but now they may need to track multiple validator sets at once to accomodate this delay.

Block Size

The ConsensusParams.BlockSize.MaxTxs was removed in favour of ConsensusParams.BlockSize.MaxBytes, which is now enforced. This means blocks are limitted only by byte-size, not by number of transactions.