Google is shutting down the program due to its improved security measures
In its email, Google states that it is closing down the program because of the "overall increase in the Android OS security posture and feature hardening efforts." This has led to researchers submitting fewer vulnerabilities than before.
In its last annual report, Google claims to have stopped 2.28 million privacy-violating apps and banned 333,000 malicious developer accounts. Last year, it also announced major improvements to Google Play Protect, including real-time scanning for Android malware. More recently, it bolstered the Play Integrity API with in-app signals to prevent fraudulent activities.
These improvements are evidently working and have led to fewer vulnerabilities being discovered in Android apps and the ecosystem.
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