Is it necessary to run the latest Git release?

I noticed that some linux distros ship with an older version of git. For example, my CentOS7 setup is using 1.8.3.1. As of now, the latest is 2.19. My question is more specific towards the precautions of running older versions of Git that may come preinstalled on a system.

Are there any precautions or issues with running older versions?

What are they and can they pose as a significant threat in your development?

I noticed there are a wide set of tools for git like gitk, git-lfs, etc... Are there older versions of git that may not include these tool sets and therefore require the user to install them manually?

Where do I find release notes per each release of Git?