Pages update by Apple leaves my files inaccessible

Apple issued a new update for Pages yesterday, the App Store indicates. This apparently involved dropping support for the oldest versions. My iMac is too old to accept system updates beyond Sierra 10.12.6, which as of yesterday means I can no longer run Pages 7.1 — attempts to open files created with that version now get me the error message “The current version [of Pages] requires OS X 10.15 or later, but you can download the last compatible version.” Well, no, I can’t. The included download link for “the last compatible version” refuses to download anything.

I recognize Apple’s need to keep upgrading both its hardware and software, but that should. be no reason to make perfectly functional older Macs useless by discontinuing access to the perfectly good apps they use. Does Apple not maintain even minimal responsibility to these ‘legacy’ apps — specifically, in my case, is there no way to let my old iMac go on running Pages 7.1?