New version 8.0.13. This version requires system 10.13 or 10.14. The intermediate versions of the version, required 10.12. The previous versions of 8 (8.0.0 dmr)accepted 10.11 but I think they withdrew the support before the initial final version.
Browsing your website, I only see the final version (not beta or prior) compatible with 10.11 version 5.7.16. In MU, they offer 5.7.17 as compatible, but the MySQL site mentions only 10.12. Are versions of 10.12 compatible with 10.11? Can I then use version 5.7.20?
Why do not they already offer support for 10.11 with security updates for some previous version? It was not my favorite, because it needs a lot of previous study to use. But the price of FileMaker, and its obsolescence made me consider this option. I see that there is no other solution to pay, and stay updated forever. With new computer as the Apple gurus send, every 9 months :-)