Even with a verified APK, Android 4.2.2 is a dead platform. Newer apps will increasingly require Google Play Services versions that are incompatible with Jelly Bean. You may find that after installing the legacy APK, some apps still fail. In this case, your best long-term solutions are:
Use only reputable, community-trusted mirrors. The most reliable source for verified, unmodified legacy APKs is APKMirror (owned by Illogical Robot LLC, a trusted name in Android). Even with a verified APK, Android 4