I have several sites under 3.6.5. Those sites doesn't require the new functions released on 3.7. (now to 3.7.2) I've saw with concern too many security fixes in short time.
Is it safe to upgrade? Or may I stay under 3.6.5 a little more?
What do you suggest?
I always recommend to keep all sites updated to the latest version available because new versions add improvements and fix bugs. There was a critical vulnerability in 3.7.0 that has been fixed (SCP protected you against it), so it's safe to update to 3.7.2.