diff --git a/app/src/amazon/java/org/tasks/billing/BillingClientImpl.java b/app/src/amazon/java/org/tasks/billing/BillingClientImpl.java
index fe0021ce0..d34b9c0c3 100644
--- a/app/src/amazon/java/org/tasks/billing/BillingClientImpl.java
+++ b/app/src/amazon/java/org/tasks/billing/BillingClientImpl.java
@@ -7,6 +7,7 @@ import static com.google.common.collect.Sets.newHashSet;
 
 import android.app.Activity;
 import android.content.Context;
+import androidx.annotation.Nullable;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.Observer;
@@ -59,10 +60,16 @@ public class BillingClientImpl implements BillingClient, PurchasingListener {
   }
 
   @Override
-  public void initiatePurchaseFlow(Activity activity, String sku, String skuType) {
+  public void initiatePurchaseFlow(
+      Activity activity, String sku, String skuType, @Nullable String oldSku) {
     PurchasingService.purchase(sku);
   }
 
+  @Override
+  public void addPurchaseCallback(OnPurchasesUpdated onPurchasesUpdated) {
+
+  }
+
   @Override
   public int getErrorMessage() {
     return 0;
diff --git a/app/src/amazon/java/org/tasks/billing/Purchase.java b/app/src/amazon/java/org/tasks/billing/Purchase.java
index 68532d83e..5131f4e73 100644
--- a/app/src/amazon/java/org/tasks/billing/Purchase.java
+++ b/app/src/amazon/java/org/tasks/billing/Purchase.java
@@ -27,4 +27,20 @@ public class Purchase {
   public String toString() {
     return "Purchase{" + "receipt=" + receipt + '}';
   }
+
+  public boolean isCanceled() {
+    return false;
+  }
+
+  public int getSubscriptionPrice() {
+    return 0;
+  }
+
+  public boolean isMonthly() {
+    return false;
+  }
+
+  public boolean isProSubscription() {
+    return true;
+  }
 }
diff --git a/app/src/generic/java/org/tasks/billing/BillingClientImpl.java b/app/src/generic/java/org/tasks/billing/BillingClientImpl.java
index 2969dc8f8..29f5a4fc5 100644
--- a/app/src/generic/java/org/tasks/billing/BillingClientImpl.java
+++ b/app/src/generic/java/org/tasks/billing/BillingClientImpl.java
@@ -2,6 +2,7 @@ package org.tasks.billing;
 
 import android.app.Activity;
 import android.content.Context;
+import androidx.annotation.Nullable;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.Observer;
 import java.util.List;
@@ -21,7 +22,13 @@ public class BillingClientImpl implements BillingClient {
   }
 
   @Override
-  public void initiatePurchaseFlow(Activity activity, String sku, String skuType) {}
+  public void initiatePurchaseFlow(
+      Activity activity, String sku, String skuType, @Nullable String oldSku) {}
+
+  @Override
+  public void addPurchaseCallback(OnPurchasesUpdated onPurchasesUpdated) {
+
+  }
 
   @Override
   public void querySkuDetails() {}
diff --git a/app/src/generic/java/org/tasks/billing/Purchase.java b/app/src/generic/java/org/tasks/billing/Purchase.java
index 253a83c24..0a0bcb15a 100644
--- a/app/src/generic/java/org/tasks/billing/Purchase.java
+++ b/app/src/generic/java/org/tasks/billing/Purchase.java
@@ -11,4 +11,20 @@ public class Purchase {
   public String toJson() {
     return null;
   }
+
+  public boolean isCanceled() {
+    return false;
+  }
+
+  public int getSubscriptionPrice() {
+    return 0;
+  }
+
+  public boolean isMonthly() {
+    return false;
+  }
+
+  public boolean isProSubscription() {
+    return false;
+  }
 }
diff --git a/app/src/generic/res/values/keys.xml b/app/src/generic/res/values/keys.xml
index cba38186f..de721def8 100644
--- a/app/src/generic/res/values/keys.xml
+++ b/app/src/generic/res/values/keys.xml
@@ -4,6 +4,6 @@
   <string name="market_url">https://f-droid.org/en/packages/org.tasks/</string>
   <string name="p_purchases">purchases_fdroid</string>
   <!--suppress CheckTagEmptyBody -->
-  <string name="manage_subscription_url"></string>
+  <string name="manage_subscription_url">%s</string>
   <string name="support_email">support@tasks.org</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/googleplay/res/values/keys.xml b/app/src/googleplay/res/values/keys.xml
index d4677e815..a1b4aebbb 100644
--- a/app/src/googleplay/res/values/keys.xml
+++ b/app/src/googleplay/res/values/keys.xml
@@ -5,6 +5,5 @@
   <string name="market_url">market://details?id=org.tasks</string>
   <string name="p_purchases">purchases</string>
   <string name="manage_subscription_url">https://play.google.com/store/account/subscriptions?sku=%s&amp;package=org.tasks</string>
-  <string name="subscription_help_url">https://tasks.org/subscribe</string>
   <string name="support_email">play-support@tasks.org</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/java/org/tasks/billing/NameYourPriceDialog.java b/app/src/main/java/org/tasks/billing/NameYourPriceDialog.java
index 7764cd3a3..d58c38134 100644
--- a/app/src/main/java/org/tasks/billing/NameYourPriceDialog.java
+++ b/app/src/main/java/org/tasks/billing/NameYourPriceDialog.java
@@ -20,7 +20,6 @@ import androidx.recyclerview.widget.RecyclerView;
 import butterknife.BindView;
 import butterknife.ButterKnife;
 import butterknife.OnClick;
-import com.android.billingclient.api.BillingClient.SkuType;
 import com.google.android.material.button.MaterialButton;
 import com.google.android.material.button.MaterialButtonToggleGroup;
 import com.google.common.collect.ContiguousSet;
@@ -137,12 +136,12 @@ public class NameYourPriceDialog extends InjectingDialogFragment implements OnPu
   protected void subscribe() {
     if (currentSubscriptionSelected() && currentSubscription.isCanceled()) {
       billingClient.initiatePurchaseFlow(
-          (Activity) context, currentSubscription.getSku(), SkuType.SUBS, null);
+          (Activity) context, currentSubscription.getSku(), SkuDetails.TYPE_SUBS, null);
     } else {
       billingClient.initiatePurchaseFlow(
           (Activity) context,
           String.format("%s_%02d", isMonthly() ? "monthly" : "annual", adapter.getSelected()),
-          SkuType.SUBS,
+          SkuDetails.TYPE_SUBS,
           currentSubscription == null ? null : currentSubscription.getSku());
     }
     billingClient.addPurchaseCallback(this);
diff --git a/app/src/main/res/values/keys.xml b/app/src/main/res/values/keys.xml
index 20aa7052f..d239ff54e 100644
--- a/app/src/main/res/values/keys.xml
+++ b/app/src/main/res/values/keys.xml
@@ -313,4 +313,5 @@
   <string name="p_google_tasks_position_hack">google_tasks_position_hack</string>
   <string name="google_tasks_position_hack">Custom order synchronization fix</string>
   <string name="google_tasks_position_hack_summary">Always perform a full synchronization to workaround https://issuetracker.google.com/issues/132432317. This setting will disable itself after seven days.</string>
+  <string name="subscription_help_url">https://tasks.org/subscribe</string>
 </resources>