How to use feature included in later versions (say 1.6+) in 1.5?

[mr-cloud]

Note that v1.7.0 was released days ago. So I really want to know the answer. Can you explain? Thanks alot.
Q1: I notice that 1.5 is a LTS version. But some release features only are included in 1.6+. So How can I use them if i stick to 1.5.
Q2: How to migrate to the later version (e.g., the next LTS version) from 1.5?
Q3: How often will FATE releae the LTS version?