Scaling Lightning Safely With Feerate-Dependent Timelocks

The email from Boris Nagaev raises queries about the alignment of a window in the context of block mining and transaction validity. More specifically, he questions why blocks mined since the last block, which has a height divisible by the window size, do not influence the validation of transactions, noting that this could mean recent changes in fees might not be reflected when confirming a transaction. Boris suggests that implementing a global window size could potentially streamline the verification process and reduce the space required in the Full Data Transaction (FDT). He proposes that an array of integers sized to the window would be adequate for determining if a certain number of blocks within the latest blocks have at least a median fee rate.

Boris' concern indicates a need for clarity on how the alignment of the window influences transaction confirmation, especially in scenarios where the transaction fees have recently changed but are not accounted for due to the alignment. His second point touches on the benefits of having a standardized global window size, implying that such an approach could simplify the verification mechanisms and improve data efficiency within transactions. This could particularly impact the verification process in cases where the window is not aligned. Boris ends his message by suggesting a method for answering whether there's been a sufficient number of blocks with a median fee rate among the latest blocks within the specified window size.