Does KIP-0021 increase storage requirements for Kaspa nodes?

No — KIP-0021 is specifically designed so that node storage does not grow asymptotically from lane commitments. A natural worry about tracking per-lane data is that storage could expand forever as more application lanes appear. KIP-0021 avoids this through an activity window called F: only lanes that have been active recently — within window F, which is kept strictly smaller than the node's pruning depth — are held in the "hot" commitment set. Once a lane goes quiet past that window, it drops out of active storage. Crucially, the design makes no assumption about a fixed cap on how many distinct lanes have ever existed; it simply bounds what must be stored right now to recent activity. For node operators, this means KIP-0021's lane commitment feature doesn't require ever-growing hardware — storage scales with current network activity, not the full historical record of every lane.