Facts and sources
Reduced Data Temporary Softfork is a consensus change proposal that aims to temporarily restrict several data-carrying constructions for 52,416 blocks, roughly one year after activation.
Rules, in short: limits or invalidates specific scriptPubKey, OP_RETURN, PUSHDATA or witness-item, undefined witness/Tapleaf version, annex, control-block, OP_SUCCESS, and OP_IF/OP_NOTIF constructions.
Activation constants in the specification: bit 4; 1109/2016 threshold; mandatory signaling blocks 961,632-963,647; lock-in no later than 963,648; latest active height 965,664. If the threshold is met earlier, the reduced-data rules activate one difficulty period after lock-in; in the late Window 476 example path shown here, that is 963,648.
Sources: BIP110 specification, BIP9, BIP8, and Bitcoin Core chainwork semantics. Last reviewed against the BIP110 specification: 2026-07-26.