You need to be aware that not everyone agrees with the necessity to upgrade with WordPress, especially the necessity to upgrade with each Version. Some people feel its more trouble than its worth and don’t see the advantage. There reaction can be as concerned as “oh no not this again” when they see that small message on their Dashboard that there is an Upgrade available.
Maybe you’re amongst this group or interested in finding out why?
It would be remiss of us not to present this view as well as one that suggests you should always upgrade that way you can consider the arguments for and against and decide for yourselves.
Those who don’t agree with upgrading have a variety of reasons why they don’t really wish to do so, including the fact that newer versions of WordPress might require new versions of plugins or the new version of WordPress may cause some plugins to become useless or ineffective.
A number also hold the view that as far as missing out on any new features (in the newer Version) is concerned, that tagging is really all you are missing out on and other tagging tools are just as, if not more, effective.
Another argument (against upgrading) is that the exercise of backing up files, databases and deactivating plugins and possibly installing new versions of same, is very time intensive and often not worth what you gain in return.
These same people make the point hat unless there is some security that needs to be fixed on some fab new functionality issue at stake (that you simply must have) than there is no need to upgrade with each new version.
Its fair enough to realise (whatever your opinion about the wisdom of upgrading or not is concerned) that some of your much loved plugins may simply not be compatible with the newer version of WordPress so do make sure (as much as you can) that you read the notes that come with the Upgrade before you perform the actions. Check things until you’re happy with them wherever possible.