QuickStart, what to smoke if you are going to switch from Centos 6.6 to Centos 7?

Question

linux

Hello!
There is a solid experience of administration of Centos/RHEL of the 6th version, now we are planning to move to the 7th.
A question for the connoisseurs who have already managed to climb over and catch all the shoals:
1) What are the major and serious changes? (eg systemd, docker, etc)
2) What are the pitfalls?
In principle, the basic features and changes will be enough, but if someone shares good material, then half the kingdom will be his wife.

Answer 1

Yes, I don't see much of a difference.

Answer 2

After running into a lot of problems, I changed my update policy.
I update only under one of the conditions:
1) If you really need some kind of feature that is not in the current version.
2) If support for security updates for the current version is discontinued.
From experience, it turned out that updating just like that (from what you just want) is not a very good solution: D.