Excuse me, but that type of statement or comment makes absolutely no sense to me and I use a similar 2011 iMac and have been able to update the Mac OS and any of the applications I use on a daily basis to a good working and safe supported situation.
If a developer chooses to maintain an app to keep it secure and continue to improve it, they'll have to start incorporating new things that become available with newer versions of the OS. While a lot of the functionality is backward compatible, some meaningful things aren't. This now means that multiple versions of the application have to be maintained.
Not being a developer, you might not understand or appreciate the nuance around this, but let me explain at a high level.
A lot of people are familiar with the concept of Stable, Canary and LTS releases of software. In short, stable is the up to date version of a software that is expected to be bug-free without any new features/functionality that requires you to learn anything new or break existing workflows. Canary (also called bleeding edge) is the exploratory version of an application with perhaps non-backward compatible changes, totally new functionality and so on. LTS (Long term support) is the version of the application that is attempts to provide the longest support runway to ensure that things work as they should.
However, everything has a lifetime. Each of these releases means potentially 3 different code bases that are growing apart on a release by release basis. Security changes need to be applied to 3 code bases and modified to fit within the constraints of that code base.
Most commercial app developers will try to follow this pattern. For example, Chrome has the stable and canary releases, they don't do LTS. Safari has the stable and preview (aka canary) releases, etc.
Independent developers will usually focus on the stable release, trying to support anything else is just too time consuming. Additionally, the bulk of the user base generally tends to upgrade computers and OS' frequently enough that this isn't an issue, so you are not going to try to address the small minority that holds onto computers past their prime.
I respect the fact that the newer later machine and software can possibly do more and have more features but not any of them that I really need or can use for that matter.
That's not how it works. Understand that over time as the OS evolves, it deprecates (and eventually) removes functionality that require app changes. This is the normal lifecycle of app development.
Not even all the new "features" of later Mac OS versions will even work on this Mac model even though Apple says they are supported in the software. What the **** use is that if they can't even be accessed or used???
I just want or need my iMac and any of my stuff I need to work properly and reliably on a daily basis, even if the equipment and software are older than often suggested as to what should be used, and the continual suggestion of one having to use the "new and improved" seems to come from those where money is the driving force to do so and often turns out to be an oxymoron for the upgrading user.
End of my rent... thanks.
Now back to the regular program, I hope.
If you're going to keep the iMac in a time capsule because it fits your needs, you're going to have to keep all apps running on it in the same time capsule to avoid breaking anything. You CANNOT do one and not do the other and then complain that the apps aren't working.
