In what year did the Taproot upgrade activate on the bitcoin network? Answer with the four-digit year only.
Which Ethereum upgrade in August 2021 introduced EIP-1559? Answer with the name only.
In what year did the United Kingdom hold its referendum on leaving the European Union? Answer with the four-digit year only.
Who became UK Prime Minister in September 2022, before Rishi Sunak? Answer with the surname only.