Basically to be short, all old ARCORE (below 1.0) is outdated in Android 8 and therefore neither of the applications going to support it. You should either re-compile them in the newest 4.18-github-google-arcore-1.0 or just re-make them in 4.19.1 following new rules, new blueprints and new API, whatever you have created in the past (below ARCore 1.0) is outdated and no longer supported by Android 8 which had automatically updated your arcore to 1.0 pretty recently. This is why we all got cut out from our applications.