It's possible to let the difficulty linearly drop as the solvetime goes beyond some limit (credit AS). If the limit is greater than any delay in the past it could be backwards-compatible.
A simple daily-rolling average DA like BCH is probably the best option if a faster DA is ever needed. As a point of research interest (not likely to be needed by BTC), I've taken the first above idea of "intra-block" timestamp-based difficulty adjustment to the limit and made it symmetrical (higher D for fast solves) and continuous. The result is a "tightening of the Poisson" that increases "availability" (predictable solution times) at an expense in "consistency" (orphans). It requires a very tight future time limit to reduce timestamp manipulation. My objective was to help small coins deal with persistent 20x hash rate changes that result in long delays. About 3 coins have it on testnet. https://github.com/zawy12/difficulty-algorithms/issues/36 _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
