I don't like systemd.

I liked CentOS 6.5, but have not liked CentOS after that.

If I went back to CentOS 6.5, would I be able to run newer apps?

CentOS V6 is supported until November 2020. It should run fine until then, and after that is you do not mind that updates will stop and security become very questionable.

CentOS V6 will run any apps in the V6 repos. If you have apps compiled specifically for RHEL V7 or CentOS V7 then you are likely to run into problems. If you can get hold of the source, you may be able to compile newer versions for use on V6, but I cannot recommend that. (Having done it myself a time or two: it was great fun and a bit of a pain.)

You may want to migrate to Debian (which supports things both ways with a bit of pain) or look at this page
http://without-systemd.org/wiki/index.php/Main_Page


There ARE supported options for avoiding systemd, but not on RHEL V7, or CentOS V7.

Best of luck!