Most software companies will support old versions of their software for a limited amount of time. Sage, our main vendor, only supports two prior versions of their software for Sage 300. A new version of Sage 300 comes out just about every year. This is not uncommon as most software vendors have a similar policy. Therefore, when Sage releases the 2019 version they will soon thereafter discontinue support for the 2016 version. Old unsupported versions will most likely still work fine in the short term, but they come with a risk.
Recently one of our clients was hit by a virus. Fortunately they have good backups and were able to mitigate the damage. They decided to update their server and all of their workstations. Support for their accounting software had stopped a few years back due to changes by Microsoft. When they installed all the new hardware they encountered a number of issues with the old software. They now are facing an unplanned upgrade. They were perfectly happy with the old software, but there is always the risk that it will not run properly with new hardware.
Now we do not recommend that you always have to upgrade to the latest version and we continue to support old software even when it no longer supported by the vendor, but we are limited in what we can do. Technology changes quickly and we do not want to hold a company back from using newer, faster and easier computer equipment and software, because they have an old accounting or ERP system. If you are currently using unsupported software we recommend replacing it as soon as possible. Definitely within the next year or two.
What you will find out when purchasing a new system is that many software companies are moving to a selling on a subscription basis. This will significantly reduce the first year cost of the software, but future years many have a larger cost. This is the way that Sage now sells most of its products and it is the way they sell Sage 300. Interestingly, the future yearly subscription price is about the same as the old annual maintenance fee. There is an activation fee in the first year and of course the cost of setting up the software, moving data and training users. We have not found a client that would pay more under the new pricing plan than if they were to purchase the software under the old method and keep paying for their annual maintenance.
The moral of the story is you can either plan to upgrade your software or wait for a disaster and be forced to upgrade. We prefer working planned updates. It is less stressful for you and easier too!