Every time you update your system, your currently running applications should be restarted otherwise you will be still running those old binaries before the update.

You have 3 options how to resolve it:

1. You ignore it completely and you patiently wait until your system crash.
2. Do Offline Updates.
3. After restart you carefully restart only those applications and daemons, which needs to be restarted.

I really dislike Offline Updates as I see no reason for going offline for dozens of minutes. And there is only few scripts which helps you when you want to follow option 3. Most famous is needs-restarting from yum-utils. But the output is very ... ehm ... unfriendly. And it is very slow.

...