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:
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https://fioprotocol.atlassian.net/browse/WP-604
The current FIO Request data type is String, so no data migration will be required.