Update rules

app/build.gradle

@@ -12,6 +12,7 @@ android {
         targetSdk 28
         ndk { abiFilters "armeabi-v7a" }
         buildConfigField("String", "CLIENT_ID", "\"${clientId}\"")
+        multiDexEnabled true
     }
 
     buildTypes {

app/proguard-rules.pro

@@ -33,8 +33,10 @@
 -keep class com.thegrizzlylabs.sardineandroid.** { *; }
 
 # Smbj
+-keep class org.bouncycastle.** { *; }
 -keep class com.hierynomus.** { *; }
--keep class net.engio.mbassy.** { *; }
+-keep class net.engio.** { *; }
+-keep class org.slf4j.** { *; }
 
 # Zxing
 -keep class com.google.zxing.** { *; }