What's new
Introducing spl-token-interface, a lighter crate that provides all instructions and struct types used by SPL Token. You can read more about how it was split out in the PR that created it: #76
Using the crate
For the most part, you should be able to drop in spl_token_interface in place of spl_token, and the rest should just work. The program id, state types and instructions are all in the same place as before. The interface crate simply doesn't have on-chain specific things, like the entrypoint and instruction processors.