Reading this Blockstack paper : https://blockstack.org/blockstack.pdf it states :
With Blockstack,
we extend the single state machine model of
blockchains to allow for arbitrary state machines without
requiring consensus breaking changes in the underlying
blockchain.
What is meant by 'consensus breaking changes' ? Is it related to once 51% consensus has been achieved that something can break ?
A consensus breaking change is one that requires everyone to upgrade their software client so that consensus is maintained. For example: updating the block size in Bitcoin. If larger blocks are implemented in Bitcoin, everyone must update their client because old software basically cannot process larger blocks. Such changes are hardforks and those who do not update their software cannot be synchronized with the blockchain.
