While APK files for various versions (including later versions like 5.11.3.5) are still hosted on third-party repositories like Uptodown , the app's functionality is severely limited:
Manual installation of an APK requires granting "Unknown Sources" or "Install Unknown Apps" permissions in Android system settings. Couples [v0.5 SE] [APK]
Common modern replacements that offer similar shared calendars and private messaging features originally found in the "Couples" app. The Couples Game – Додатки в Google Play While APK files for various versions (including later