# V3 and some possible futures

**URL:** <https://delvingbitcoin.org/t/v3-and-some-possible-futures/523>\
**Category:** Protocol Design\
**Created:** [February 6, 2024, 6:11pm UTC](https://delvingbitcoin.org/t/v3-and-some-possible-futures/523 "2024-02-06T18:11:07Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![instagibbs](https://delvingbitcoin.org/user_avatar/delvingbitcoin.org/instagibbs/32/28_2.png) [@instagibbs](https://delvingbitcoin.org/u/instagibbs)\
**Post date:** [March 27, 2024, 2:47pm UTC](https://delvingbitcoin.org/t/v3-and-some-possible-futures/523/4 "2024-03-27T14:47:40Z")

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Just noting publicly here:

For “top block” style systems we would have to ensure that _all resulting clusters_ remain “top block”, otherwise pinning can trivially happen by creating a top block cluster, then “cycling” away the CPFP on a large low-fee parent transaction. Ensuring each state transition results in “top block” is essential.

These kinds of checks can likely be achieved, and state transitions simply rejected on failure, but it’s a bit more complicated than I was hoping!

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