On its website it is established that the new version 1.9 requires 10.12, however in the readme it is mentioned 10.9, without specifying that this and others below 10.12 require an earlier version. It seems that the version of the disk image requires that 10.9 that you mention.
Furthermore, the application’s info.plist file also mentions 10.9 as a requirement. This makes apps like MacUpdate consider that the version also requires 10.9 and does not mention the change.
Both for users and for those program update services, it would be interesting if the information was consistent. Or at least that the readme file was clear about the requirements of the version to install.
One of the advantages that came to the program when I began to think about replacing DEVONthink was precisely its low requirements, which in my case are fundamental since I still use two macs with 10.11. And it seems to me very appreciated that they continued to offer support to those systems.
Now is the time to abandon them, but at least they continue to include information about the previous versions that do support them, something I appreciate. Many others consider all these versions to be disappeared in limbo, but they are still of interest to many users. And it is something totally necessary. For me, true ecology is demonstrated in these details. Even more basic than making new products with materials with an ecological sticker. The true ecology consists of extending to the maximum the useful life of the products. And that in computing happens to maintain software support for these products. Thank you.
P.S. Mechanically translated message as I do not speak English, I apologize if it is not understood or I have not expressed myself correctly.
Greetings
Jose Luis
Sorry for the confusion. The information is usually consistent. What happened this time is that I discovered after shipping the update that it crashes at launch on 10.11. Although the code is written and compiled to work back to 10.9, there was a change in Xcode that makes the binary not link properly on 10.11, causing the crash. This seems to be a widespread issue going back years, so I’m not expecting a fix from Apple. I can’t go back to the old way of building EagleFiler, which avoided that problem, because then it would not be possible to fully support macOS 11 Big Sur. So, for now at least, the “fix” was to update the site and software update feature to require 10.12 so that people don’t download a version that they can’t use. Longer term, I may be able to bring back support for macOS 10.11.
The Read Me and Info.plist will be updated in the next release. MacUpdate shows the correct requirements now. They don’t read the Info.plist; they just don’t always update the information that we submit. (The icon still has not been updated despite several submissions…)
You can download previous versions of EagleFiler here, and the library format is compatible so that you can use an older version on your 10.11 Macs and open the same library with EagleFiler 1.9 on a newer Mac.
Thanks for answering.
Obviously, I preferred that they could make it backwards compatible 
but I understand that sometimes you can’t.
What I asked is that at least those requirements be updated both on the web (which was already there) and in the application’s readme.
I used MacUpdate before, but discovering MacUpdater with a lower price and initially more support for “old” systems I changed.
And in their support, on several occasions they tell me that they get the requirements from the same program. In fact, in many that it proposes to update when doing so, the program recognizes the changes according to the new application package. Although in other cases, they manually make the appropriate adjustments if asked.
But, they no longer accept rectifications from “old” systems. Not even to recognize those problems with the requirements, something fundamental in order to update a program or not.
Thanks again. And best regards.
Jose Luis