> directory of APKs sorted by version Something like that already exists. I had to use one of these directories once to install an older release of Signal on a

> directory of APKs sorted by version Something like that already exists. I had to use one of these directories once to install an older release of Signal on a relative's phone (newer releases of Signal don't work on older phones, older releases of Signal aren't compatible with the current Signal server, but there's a single version in the middle which both works on older phones and is compatible with the current Signal server; unfortunately, that phone hadn't yet updated to that release before a newer release went out).