What values are legal for the transaction's version field? In the transaction's version field, what values are legal?

What values have actually been seen in the blockchain?
In the transaction's version field, what values are legal?


The version field is a 32 bit unsigned integer, any value is valid. Version 0, or version numbers above the nodes CURRENT_VERSION constant are considered non-standard and are not relayed, though they can appear in blocks. 


  What values have actually been seen in the blockchain?


1 is the only number to have been in use at this point in time. BIP62 proposes bumping the version to 3 (skipping 2 entirely) to match the block version and avoid confusion, however this was withdrawn. BIP68 specifies that transactions spending a CSV output must have version 2 or higher.