My first thoughts are I haven't heard of Blockchain 3.0 but I have heard of Web 3.0 coming soon.

I went and did a quick Google search on the topic of Blockchain 3.0 and found that Blockchain 1.0 is actually Bitcoin, Litecoin, and all the alt-coins that were there from the beginning. Next is Blockchain 2.0 which are modern alt-coins that delve into privacy, smart contracts, and all that good stuff. So based off of the changes from 1.0 to 2.0 that means 3.0 will require a drastic change in technology so who knows maybe soon some alt-coins will come up with new revolutionized tech that will be labeled as Blockchain 3.0.

(Also you might want to move this topic to the Alt-coins board  )