BOLT12 x Rust Lightning
'An initial version of async payments is now supported. The current implementation is specific to LDK and only LDK supports paying static invoices. However, because BOLT 12 invoice requests will gracefully "upgrade" to a non-static invoice when the recipient comes online, offers backed by static invoices are expected to be payable by any BOLT 12 payer.'
https://github.com/lightningdevkit/rust-lightning/releases/tag/v0.2.0-rc2