This update brings a massive rework to how blocks behave on the backend (code side). If you're someone with massive lag from blocks this will fix it is really all you need to know.
Although if you're looking for more information on how the rework is done you can continue reading.
Basically before each block acted as it's own entity that contained information like block color, block type (stairs, pole, slab, etc) block position as well as block health.
When you would have building with easily 200-500 blocks on the low end then some players hitting 5,000 plus with just a few hours of playtime this creates massive issues as loads of data points are being computed a lot. Every single time Hamsters needed to pathfind (navigate) the blocks they would need to collect all this information on where they can and can't go creating even more lag. This rework solves this, it "chunks" blocks together. So a build with 40,000 blocks actually turns into only about 20 blocks. What happens is it takes blocks in a certain radius and all their data and combines them into one object. This one object now only stores the information of the coordinates of each block as well as the stats listed before. Therefore you have basically a few "master" locations to do the computation through instead of a bunch of random ones. This is a pretty standard system for most games that are going to be using building, although early on I didn't think players would build some of the massive things they did. Soon I realized... I was wrong. Therefore this was a long overdue update needed. Thank you and enjoy!