diff --git a/muzei-nationalgeographic/proguard-rules.pro b/muzei-nationalgeographic/proguard-rules.pro
index 8abc807..01df6ed 100644
--- a/muzei-nationalgeographic/proguard-rules.pro
+++ b/muzei-nationalgeographic/proguard-rules.pro
@@ -5,6 +5,9 @@
 -dontwarn okhttp3.**
 -dontwarn okio.**
 -dontwarn retrofit2.**
+-keep class retrofit2.** { *; }
+
+-dontwarn lombok.**
 
 # GSON and R8 don't come along very well
 -keepclassmembers,allowobfuscation class * {
diff --git a/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Feed.kt b/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Feed.kt
index c0803b6..7d4be3c 100644
--- a/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Feed.kt
+++ b/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Feed.kt
@@ -1,7 +1,9 @@
 package de.msal.muzei.nationalgeographic.model
 
+import androidx.annotation.Keep
 import com.google.gson.annotations.SerializedName
 
+@Keep
 data class Feed(
       @SerializedName("images") val items: List<Item>
 )
diff --git a/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Image.kt b/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Image.kt
index f393e7e..7e96523 100755
--- a/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Image.kt
+++ b/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Image.kt
@@ -1,7 +1,9 @@
 package de.msal.muzei.nationalgeographic.model
 
+import androidx.annotation.Keep
 import com.google.gson.annotations.SerializedName
 
+@Keep
 data class Image(
       @SerializedName("alt") val altDescription : String?,
       @SerializedName("title") var title : String?,
diff --git a/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Item.kt b/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Item.kt
index 944adcf..a329ef9 100644
--- a/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Item.kt
+++ b/muzei-nationalgeographic/src/main/kotlin/de/msal/muzei/nationalgeographic/model/Item.kt
@@ -1,8 +1,10 @@
 package de.msal.muzei.nationalgeographic.model
 
+import androidx.annotation.Keep
 import com.google.gson.annotations.SerializedName
 import java.util.*
 
+@Keep
 data class Item(
       @SerializedName("entityLabel") val entityLabel : String?,
       var date : Calendar?,