Program patches to fix security issues in programs can come out at any time and are usually freely available to anyone who has the original program installed. It is usually essential that you install such patches as soon as possible so as to ensure the ongoing integrity of your computer's security since not installing the patch may result in your computer containing a known security hole that can be exploited. The same applies even more so to any scripts you might have installed on your web site (if you have one).
Major program upgrades are a slightly different situation. In these cases the new version is not fixing security holes, it is adding new functionality. In the case of programs that you have to purchase in the first place you will probably have to pay at least a nominal upgrade fee in order to obtain this type of upgrade.
Installing a major upgrade of a program you already have installed is far less important than installing minor upgrades.For one thing you may not need the additional functionality. If the existing version does everything you need then why get the new version?
Of course provided that the new version still supports doing everything that the current version does in the same way the current version does it and offers the new features in addition to that then upgrading will be relatively straightforward if you decide that the new features will be useful.
If the new version has completely redesigned the interfact so that all the options are accessed in an entirely different and supposedly more straightforward way then as long as they still provide the option to use the old interface with the new version then you can upgrade with no problems. You can try out the new interface and if it slows you down too much then you can switch back to the old interface whenever you need to get something done quickly until such time as you learn the new interface properly and can use it quicker than you can use the old one. That's assuming the new interface actually is better and that the reason using the old one is faster to start with is due to your knowing how to use it.
The problem with major upgrades comes when they start removing functionality that you actually use and don't provide an adequate replacement. I have had this happen with several programs that I run myself.
The web editor I use was at version 3 when I first started using it. The last time I looked at upgrades it was at version 9 and could very well be at version 10 or 11 at the time of my writing this. I currently run version 8. I did originally upgrade to version 9 but some of the features that I specifically chose that editor for stopped working properly in that version. I did report those issues to the owners of the software and was eventually advised that the changes had been made for efficiency reasons. They were also kind enough to provide a patch that I could install to get the feature I wanted working again (with reduced program efficiency) and was also offered a discount if I wanted to upgrade to one of the two more advanced versions of the editor. Since neither of the more advanced versions offered any features that I wanted and version 8 doesn't seem to suffer from the efficiency issued that version 9 does I immediately switched back to running version 8. If there are ever any security issues with regard to the version I am running and an appropriate version 8 patch is not going to be released (since it is no longer the latest version) then I will be hunting around for a completely different editor and will drop the current editor completely since the later version does not do what I need.
I have more recently had a similar experience with the email program that I use. The new version 3 adds a number of new features that I don't need without there being any easy way to turn them off. It also changes the way some things work so that they now work in a slightly different way than they used to. In version 2 (which I am once again using) deleting an email automatically loads the next email into the same window if there is a next email in the same folder. If I delete the last email in the folder the window closes. Version 3 gives a choice between closing the window after every delete (and thus having to open it again) or if you allow it to load the next email automatically then when it gets to the end of the folder it starts loading prior emails that are in the folder that have already previouly been read and which are to be kept. That means that it is no longer possible to tell when I have finished reading through and deleting all of the outstanding emails in the folder. Since there are several functional changes in the new version that make it impossible for me to work through my emails in the way that I prefer, the only option available to me was to revert back to the prior version. So now I have another program where I will be searching for a replacement if the version I am running ever needs a security patch and doesn't get one because of not being the current version.
It is bad enough when the place you got a program from decides to abandon their program and so no further patches will be available because the program isn't supported any more. At least that is understandable though and in many cases such programs will not be common enough to make them targets for attack anyway. Programs where upgrades break the functionality that you decided to use them for in the first place are not quite so easy to understand (why didn't they at least offer the option to maintain the current way of working) and are perhaps bigger targets. That makes it more likely that you will eventually have to find a different program to perform that task and perhaps ought to keep that in mind so as to be able to check out alternative programs when you find them even though the existing program is still usable.
The biggest problem is that some programs are easier to replace than others. In selecting a replacement web editor for if the one I am currently using ever becomes a security issue it is simply a matter of installing alternative editors on the computer and trying them out. When I decide to switch I can simply change a few file type associations and delete the old program. Trying out an alternative email program is nowhere near as simple and so I will have to be a lot more selective about possible alternatives and whether they can work the way I need them to before I even attempt to install them.
It is all the fault of the program designers. Why do they insist on taking a program that works and removing useful functions from it along with adding the new functions. Not everyone wants the new functions and some people need the old ones.
This article written by Stephen Chapman, Felgall Pty Ltd.