With Google's introduction of 64-bit ABIs for Android, we need to make some minor updates to Version Codes we use to publish and filter app on Google Play. The current suggestion make the 64-bit ABI 1 higher than the 32-bit code, making the 64-bit the preferred.
The ABI key is: 7 - x86_64, 6 - x86, 3 - ARM64-V8A, 2 - ARMv7, 1 - ARMv5TE. A suggested scheme for your version codes, using the first digit for the ABI, the second and third digits for the API Level, the fourth and fifth digits for the minimum and maximum screen size (1 - 4 indicating each of the four sizes) or to denote the texture formats and the last three digits for the app version. The ABI key is: 7 - x86_64, 6 - x86, 2 - ARMv7, 1 - ARMv5TE. For example, the version code for x86_64 ABI and an API level 19 APK would be something like 71900310.