Also, later block numbers are not necessarily more advance. Some were built for different roles or for different countries with different requirements, so they may have various capabilities and limitations that are not always "better" than a lower block number.
That said, a higher block number is usually newer than a lower block number. Except that production blocks may have run concurrently, and some aircraft in some blocks for some customers were not delivered so they may be "new" in the sense that they have almost no flight time, but have been in storage for a while.