diff --git a/eng/versioning/version_client.txt b/eng/versioning/version_client.txt
index d21b021f3f34..6bcb9d87bf40 100644
--- a/eng/versioning/version_client.txt
+++ b/eng/versioning/version_client.txt
@@ -257,7 +257,7 @@ com.azure.spring:spring-cloud-azure-stream-binder-servicebus;4.16.0;4.17.0-beta.
 com.azure.spring:spring-cloud-azure-trace-sleuth;4.16.0;4.17.0-beta.1
 com.azure.resourcemanager:azure-resourcemanager;2.36.0;2.37.0-beta.1
 com.azure.resourcemanager:azure-resourcemanager-appplatform;2.36.0;2.37.0-beta.1
-com.azure.resourcemanager:azure-resourcemanager-appservice;2.36.0;2.37.0-beta.1
+com.azure.resourcemanager:azure-resourcemanager-appservice;2.36.1;2.37.0-beta.1
 com.azure.resourcemanager:azure-resourcemanager-authorization;2.36.0;2.37.0-beta.1
 com.azure.resourcemanager:azure-resourcemanager-cdn;2.36.0;2.37.0-beta.1
 com.azure.resourcemanager:azure-resourcemanager-compute;2.36.0;2.37.0-beta.1
diff --git a/sdk/resourcemanager/azure-resourcemanager-appservice/CHANGELOG.md b/sdk/resourcemanager/azure-resourcemanager-appservice/CHANGELOG.md
index c54d637a95f4..655c65125f99 100644
--- a/sdk/resourcemanager/azure-resourcemanager-appservice/CHANGELOG.md
+++ b/sdk/resourcemanager/azure-resourcemanager-appservice/CHANGELOG.md
@@ -10,6 +10,13 @@
 
 ### Other Changes
 
+## 2.36.1 (2024-03-04)
+
+### Bugs Fixed
+
+- Fixed NullPointerException when updating Function App in Azure Container Apps.
+- Fixed a bug that `withPrivateRegistryImage` doesn't work as expected for Function App in Azure Container Apps.
+
 ## 2.36.0 (2024-02-29)
 
 ### Other Changes
diff --git a/sdk/resourcemanager/azure-resourcemanager-appservice/assets.json b/sdk/resourcemanager/azure-resourcemanager-appservice/assets.json
index ae1487d0da68..6c164a5492b8 100644
--- a/sdk/resourcemanager/azure-resourcemanager-appservice/assets.json
+++ b/sdk/resourcemanager/azure-resourcemanager-appservice/assets.json
@@ -2,5 +2,5 @@
   "AssetsRepo": "Azure/azure-sdk-assets",
   "AssetsRepoPrefixPath": "java",
   "TagPrefix": "java/resourcemanager/azure-resourcemanager-appservice",
-  "Tag": "java/resourcemanager/azure-resourcemanager-appservice_b33aba24fe"
+  "Tag": "java/resourcemanager/azure-resourcemanager-appservice_c5279701f3"
 }
diff --git a/sdk/resourcemanager/azure-resourcemanager-appservice/src/main/java/com/azure/resourcemanager/appservice/implementation/FunctionAppImpl.java b/sdk/resourcemanager/azure-resourcemanager-appservice/src/main/java/com/azure/resourcemanager/appservice/implementation/FunctionAppImpl.java
index 63a3efd5e980..38ca4916b624 100644
--- a/sdk/resourcemanager/azure-resourcemanager-appservice/src/main/java/com/azure/resourcemanager/appservice/implementation/FunctionAppImpl.java
+++ b/sdk/resourcemanager/azure-resourcemanager-appservice/src/main/java/com/azure/resourcemanager/appservice/implementation/FunctionAppImpl.java
@@ -59,6 +59,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.MalformedURLException;
+import java.net.URL;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -415,7 +416,17 @@ public FunctionAppImpl withPrivateDockerHubImage(String imageAndTag) {
     @Override
     public FunctionAppImpl withPrivateRegistryImage(String imageAndTag, String serverUrl) {
         ensureLinuxPlan();
-        return super.withPrivateRegistryImage(imageAndTag, serverUrl);
+        super.withPrivateRegistryImage(imageAndTag, serverUrl);
+        if (isFunctionAppOnACA()) {
+            try {
+                URL url = new URL(serverUrl);
+                // remove URL protocol, as ACA don't allow that
+                withAppSetting(SETTING_REGISTRY_SERVER, url.getAuthority() + url.getFile());
+            } catch (MalformedURLException e) {
+                // NO-OP, server url is not in URL format
+            }
+        }
+        return this;
     }
 
     @Override
@@ -646,7 +657,7 @@ private void adaptForFunctionAppOnACA() {
             siteConfigInner.withLinuxFxVersion(this.siteConfig.linuxFxVersion());
             siteConfigInner.withMinimumElasticInstanceCount(this.siteConfig.minimumElasticInstanceCount());
             siteConfigInner.withFunctionAppScaleLimit(this.siteConfig.functionAppScaleLimit());
-            siteConfigInner.withAppSettings(this.siteConfig.appSettings());
+            siteConfigInner.withAppSettings(this.siteConfig.appSettings() == null ? new ArrayList<>() : this.siteConfig.appSettings());
             if (!appSettingsToAdd.isEmpty() || !appSettingsToRemove.isEmpty()) {
                 for (String settingToRemove : appSettingsToRemove) {
                     siteConfigInner.appSettings().removeIf(kvPair -> Objects.equals(settingToRemove, kvPair.name()));
diff --git a/sdk/resourcemanager/azure-resourcemanager-appservice/src/test/java/com/azure/resourcemanager/appservice/FunctionAppsTests.java b/sdk/resourcemanager/azure-resourcemanager-appservice/src/test/java/com/azure/resourcemanager/appservice/FunctionAppsTests.java
index 757395ab6b6c..6e8c21a96659 100644
--- a/sdk/resourcemanager/azure-resourcemanager-appservice/src/test/java/com/azure/resourcemanager/appservice/FunctionAppsTests.java
+++ b/sdk/resourcemanager/azure-resourcemanager-appservice/src/test/java/com/azure/resourcemanager/appservice/FunctionAppsTests.java
@@ -529,6 +529,10 @@ public void canCreateAndUpdateFunctionAppOnACA() {
         Assertions.assertEquals("mySettingValue", functionApp.getAppSettings().get("customSetting").value());
 //        Assertions.assertEquals("connectionValue", functionApp.getConnectionStrings().get("connectionName").value());
 
+        functionApp.update()
+            .withPublicDockerHubImage("mcr.microsoft.com/azure-functions/dotnet7-quickstart-demo:1.0")
+            .apply();
+
         functionApp.update()
             .withMaxReplicas(15)
             .apply();
@@ -560,6 +564,8 @@ public void canCreateAndUpdateFunctionAppOnAcaWithPrivateRegistryImage() {
         Assertions.assertThrows(ManagementException.class, () -> appServiceManager
             .serviceClient().getWebApps().getByResourceGroup(rgName1, webappName1));
 
+        String password = "PASSWORD";
+
         String managedEnvironmentId = createAcaEnvironment(region, resourceGroup);
         appServiceManager
             .functionApps()
@@ -569,8 +575,8 @@ public void canCreateAndUpdateFunctionAppOnAcaWithPrivateRegistryImage() {
             .withManagedEnvironmentId(managedEnvironmentId)
             .withMaxReplicas(10)
             .withMinReplicas(3)
-            .withPrivateRegistryImage("xiaofeiacr.azurecr.io/samples/nginx:latest", "xiaofeiacr.azurecr.io")
-            .withCredentials("xiaofeiacr", "PASSWORD")
+            .withPrivateRegistryImage("samples/nginx:latest", "https://xiaofeiacr.azurecr.io")
+            .withCredentials("xiaofeiacr", password)
             .withRuntimeVersion("4")
             .create();
 
@@ -584,6 +590,8 @@ public void canCreateAndUpdateFunctionAppOnAcaWithPrivateRegistryImage() {
 
         functionApp.update()
             .withMaxReplicas(15)
+            .withPrivateRegistryImage("xiaofeiacr.azurecr.io/samples/nginx:latest", "https://xiaofeiacr.azurecr.io")
+            .withCredentials("xiaofeiacr", password)
             .withNewStorageAccount(generateRandomResourceName("as", 15), StorageAccountSkuType.STANDARD_LRS)
             .apply();
 
@@ -592,6 +600,13 @@ public void canCreateAndUpdateFunctionAppOnAcaWithPrivateRegistryImage() {
         Assertions.assertEquals(3, functionApp.minReplicas());
 
         Assertions.assertNotEquals(connectionString, functionApp.getAppSettings().get(KEY_AZURE_WEB_JOBS_STORAGE).value());
+
+        // when serverUrl has no protocol(https), use imageAndTag directly
+        functionApp.update()
+            .withMaxReplicas(15)
+            .withPrivateRegistryImage("xiaofeiacr.azurecr.io/samples/nginx:latest", "xiaofeiacr.azurecr.io")
+            .withCredentials("xiaofeiacr", password)
+            .apply();
     }
 
     private String createAcaEnvironment(Region region, ResourceGroup resourceGroup) {