Intro
Lightning Network (LN) is a Bitcoin Layer 2 network which allows users to open payment channels between each other and exchange Bitcoin payments without the need to settle to Layer 1 on every transaction. Addressing in LN is accomplished via invoices in accordance with BOLT #11: Invoice Protocol for Lightning Payments.
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This will make 139 characters available for LN invoice. Unfortunately this is not sufficient for most LN invoices. This means that the current FIO Request structure does not support LN invoices.
Recommended Solution
Propose a FIP which will increase the allowed size of FIO Request content field and would consider the following:
Increase fees to accommodate extra size.
Make fees dynamic, akin to msig_propose and auth_update and extend the concept to bundled transactions.
Keep fees unchanged as https://fioprotocol.atlassian.net/browse/WP-119 is coming, which will likely reduce size of state.