Depends on what kind of upgrade you are planning to do. If you stay within the same release (i.e. 6.0.11 -> 6.0.12, 6.2.4 -> 6.2.7, ...) then the update is primarily dealing with bug fixes. If you don't experience any bugs you might not have to update your version within the same release train (6.0.x, 6.2.x, 6.4.x). If you however want to take advantage of new features then you want to upgrade from one train to another (i.e. 6.0.x to 6.4.x). If you follow the correct upgrade path you normally don't lose any configuration items. However if you decide to not follow the suggested upgrade path there is a chance you might lose some configuration items since they were not converted properly during the upgrades.
Version 7.0.0 has just been released. Regardless of what version you decide to upgrade to, it is always a good idea to read the readme notes before doing an upgrade to better understand what the upgrade is fixing, what features are added, and what known issues might still be there with the new version.