T.Flex Android is distributed in two variants: through Google Play or as a standalone APK.
Most smartphone users should take the Google Play route, because it is easy, familiar and takes advantage of automatic updates. For details, see Installing from Google Play.
The standalone APK option is mainly intended for devices that do not provide access to Google Play or have no touchscreen (this is common in Android-based handheld radio lookalikes). For details, see Installing from APK.
To the Android OS, the two variants of T.Flex are different applications, and it does not prevent installation and use of both of them on the same device. TASSTA GmbH does not support this configuration, even though the two variants may coexist to some degree. No testing or development is done for this kind of combination.