Protocol 19 Documentation

[Shaptic]

Once Protocol 19 is voted in, it will introduce two CAPs, CAP-21 and CAP-40, alongside a new StrKey (see SEP-23) for signed payload signers.

Documentation work includes the following:

• [x] Changes to the Horizon API: the transactions and accounts objects have new, optional fields (see the community SDK blast for a summary of changes)
• [x] Signed payloads as an alternate signature type
• [x] A discussion of the new preconditions in both transaction attributes and transaction validity
• [x] The new txMALFORMED error code as a transaction result code
• [ ] Possibly, a new glossary entry on payment channels, or amendments to Channels