Add keep rule to retain generic signature of Call
# Retrofit does reflection on method and parameter annotations.
-keepattributes RuntimeVisibleAnnotations, RuntimeVisibleParameterAnnotations
+# Keep annotation default values (e.g., retrofit2.http.Field.encoded).
+-keepattributes AnnotationDefault
+
# Retain service method parameters when optimizing.
-keepclassmembers,allowshrinking,allowobfuscation interface * {
@retrofit2.http.* <methods>;
# and replaces all potential values with null. Explicitly keeping the interfaces prevents this.
-if interface * { @retrofit2.http.* <methods>; }
-keep,allowobfuscation interface <1>
+
+# Keep generic signature of Call (R8 full mode strips signatures from non-kept items).
+-keep,allowobfuscation,allowshrinking interface retrofit2.Call
