diff --git a/proguard.flags b/proguard.flags
index ebc8922..1c79a2d 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -6,24 +6,27 @@
 
 # Keep deprecated GSM SMS API
 -keepclasseswithmembers class android.telephony.gsm.SmsManager,android.telephony.gsm.SmsManager$* {
-public *;
+    public *;
 }
 -keepclasseswithmembers class android.telephony.gsm.SmsMessage,android.telephony.gsm.SmsMessage$* {
-public protected *;
+    public protected *;
 }
 
 # Keep telephony sysprop
 -keepclasseswithmembers class android.internal.telephony.sysprop.TelephonyProperties {
-public *;
+    public *;
 }
 
 # Keep public classes and public/protected members
 -keepclasseswithmembers class com.android.internal.telephony.** {
-public protected *;
+    public protected *;
 }
 
 # Keep classes and members that have the @UnsupportedAppUsage annotation
--keep @**.UnsupportedAppUsage class *
+# TODO(b/373579455): Evaluate if <init> needs to be kept.
+-keep @**.UnsupportedAppUsage class * {
+    void <init>();
+}
 -keepclassmembers class * {
-@**.UnsupportedAppUsage *;
+    @**.UnsupportedAppUsage *;
 }