UpgradeFields are the fields in a channel end which may be changed during a channel upgrade.
Normally the RevisionHeight is incremented at each height while keeping RevisionNumber the same. However some consensus algorithms may choose to reset the height in certain conditions e.g. hard forks, state-machine breaking changes In these cases, the RevisionNumber is incremented so that height continues to be monitonically increasing even as the RevisionHeight gets reset
A successful response.
Upgrade is a verifiable type which contains the relevant information for an attempted upgrade. It provides the proposed changes to the channel end, the timeout for this upgrade attempt and the next packet sequence which allows the counterparty to efficiently know the highest sequence it has received. The next sequence send is used for pruning and upgrading from unordered to ordered channels.