While looking up how a block get mined I stumbled over the version number in the header - which is used to "keep track of changes to the protocol".
But even in the last 5 blocks of the chain (at the state of writing) there were 4 different version numbers - so my questions are:
"What does the version number represent?" followed by "Will a mined block with a random version number get rejected - or could a miner simply use it as an extension of nounce (and thereby effectively double the length of the nounce)
