We propose: BIP-XXXX: Removal of Witness Discount and Restoration of Serialized Block Size Limit
BIP-?: Removal of Witness Discount — ARTEL 21
Wasn't SegWit already deployed as a soft fork? How is removing the discount also a soft fork?
SegWit was technically a soft fork: old nodes continued to accept blocks because they validated only the stripped serialization (without witness data), which remained within the 1,000,000-byte limit. However, the deployment introduced entirely new consensus concepts that did not exist before: witness data as a separate serialization stream, block weight as a new accounting dimension, virtual size (vsize) as a user-facing abstraction, and the WITNESS_SCALE_FACTOR as an arbitrary multiplier. These concepts were not present in the pre-SegWit protocol. Old nodes did not validate them; they simply did not see them.
This proposal removes those added concepts and returns to a single, transparent metric: serialized bytes. The rule change is a soft fork because the valid block set is strictly reduced. Any block valid under a 1,000,000-byte serialized limit is automatically valid under the current weight limit, because weight = stripped_size × 3 + total_size ≤ 4 × total_size ≤ 4,000,000.