diff --git a/src/app/Handlers/Groupware.php b/src/app/Handlers/Activesync.php
copy from src/app/Handlers/Groupware.php
copy to src/app/Handlers/Activesync.php
--- a/src/app/Handlers/Groupware.php
+++ b/src/app/Handlers/Activesync.php
@@ -2,14 +2,14 @@
 
 namespace App\Handlers;
 
-class Groupware extends \App\Handlers\Base
+class Activesync extends \App\Handlers\Base
 {
     public static function entitleableClass()
     {
         return \App\User::class;
     }
 
-    public static function preReq($entitlement, $user)
+    public static function preReq($entitlement, $object)
     {
         if (!$entitlement->sku->active) {
             \Log::error("Sku not active");
diff --git a/src/app/Handlers/Groupware.php b/src/app/Handlers/Auth2F.php
copy from src/app/Handlers/Groupware.php
copy to src/app/Handlers/Auth2F.php
--- a/src/app/Handlers/Groupware.php
+++ b/src/app/Handlers/Auth2F.php
@@ -2,14 +2,14 @@
 
 namespace App\Handlers;
 
-class Groupware extends \App\Handlers\Base
+class Auth2F extends \App\Handlers\Base
 {
     public static function entitleableClass()
     {
         return \App\User::class;
     }
 
-    public static function preReq($entitlement, $user)
+    public static function preReq($entitlement, $object)
     {
         if (!$entitlement->sku->active) {
             \Log::error("Sku not active");
diff --git a/src/app/Handlers/Base.php b/src/app/Handlers/Base.php
--- a/src/app/Handlers/Base.php
+++ b/src/app/Handlers/Base.php
@@ -26,4 +26,15 @@
     {
         //
     }
+
+    /**
+     * The priority that specifies the order of SKUs in UI.
+     * Higher number means higher on the list.
+     *
+     * @return int
+     */
+    public static function priority(): int
+    {
+        return 0;
+    }
 }
diff --git a/src/app/Handlers/Groupware.php b/src/app/Handlers/Groupware.php
--- a/src/app/Handlers/Groupware.php
+++ b/src/app/Handlers/Groupware.php
@@ -18,4 +18,15 @@
 
         return true;
     }
+
+    /**
+     * The priority that specifies the order of SKUs in UI.
+     * Higher number means higher on the list.
+     *
+     * @return int
+     */
+    public static function priority(): int
+    {
+        return 80;
+    }
 }
diff --git a/src/app/Handlers/Mailbox.php b/src/app/Handlers/Mailbox.php
--- a/src/app/Handlers/Mailbox.php
+++ b/src/app/Handlers/Mailbox.php
@@ -36,4 +36,15 @@
 */
         return true;
     }
+
+    /**
+     * The priority that specifies the order of SKUs in UI.
+     * Higher number means higher on the list.
+     *
+     * @return int
+     */
+    public static function priority(): int
+    {
+        return 100;
+    }
 }
diff --git a/src/app/Handlers/Storage.php b/src/app/Handlers/Storage.php
--- a/src/app/Handlers/Storage.php
+++ b/src/app/Handlers/Storage.php
@@ -14,8 +14,24 @@
 
     public static function preReq($entitlement, $object)
     {
+        if (!$entitlement->sku->active) {
+            \Log::error("Sku not active");
+            return false;
+        }
+
         // TODO: The storage can not be modified to below what is already consumed.
 
         return true;
     }
+
+    /**
+     * The priority that specifies the order of SKUs in UI.
+     * Higher number means higher on the list.
+     *
+     * @return int
+     */
+    public static function priority(): int
+    {
+        return 90;
+    }
 }
diff --git a/src/app/Http/Controllers/API/SkusController.php b/src/app/Http/Controllers/API/SkusController.php
--- a/src/app/Http/Controllers/API/SkusController.php
+++ b/src/app/Http/Controllers/API/SkusController.php
@@ -53,7 +53,7 @@
     public function index()
     {
         $response = [];
-        $skus = Sku::select()->orderBy('title')->get();
+        $skus = Sku::select()->get();
 
         // Note: we do not limit the result to active SKUs only.
         //       It's because we might need users assigned to old SKUs,
@@ -65,6 +65,10 @@
             }
         }
 
+        usort($response, function ($a, $b) {
+            return ($b['prio'] <=> $a['prio']);
+        });
+
         return response()->json($response);
     }
 
@@ -137,6 +141,7 @@
         $data['handler'] = $handler;
         $data['readonly'] = false;
         $data['enabled'] = false;
+        $data['prio'] = $sku->handler_class::priority();
 
         // Use localized value, toArray() does not get them right
         $data['name'] = $sku->name;
@@ -145,6 +150,14 @@
         unset($data['handler_class']);
 
         switch ($handler) {
+            case 'activesync':
+                $data['required'] = ['groupware'];
+                break;
+
+            case 'auth2f':
+                $data['forbidden'] = ['activesync'];
+                break;
+
             case 'storage':
                 // Quota range input
                 $data['readonly'] = true; // only the checkbox will be disabled, not range
diff --git a/src/database/seeds/SkuSeeder.php b/src/database/seeds/SkuSeeder.php
--- a/src/database/seeds/SkuSeeder.php
+++ b/src/database/seeds/SkuSeeder.php
@@ -123,5 +123,31 @@
                 'active' => false,
             ]
         );
+
+        Sku::create(
+            [
+                'title' => '2fa',
+                'name' => '2-Factor Authentication',
+                'description' => 'Two factor authentication for webmail and administration panel',
+                'cost' => 0,
+                'units_free' => 0,
+                'period' => 'monthly',
+                'handler_class' => 'App\Handlers\Auth2F',
+                'active' => true,
+            ]
+        );
+
+        Sku::create(
+            [
+                'title' => 'activesync',
+                'name' => 'Activesync',
+                'description' => 'Mobile synchronization',
+                'cost' => 100,
+                'units_free' => 0,
+                'period' => 'monthly',
+                'handler_class' => 'App\Handlers\Activesync',
+                'active' => true,
+            ]
+        );
     }
 }
diff --git a/src/resources/vue/User/Info.vue b/src/resources/vue/User/Info.vue
--- a/src/resources/vue/User/Info.vue
+++ b/src/resources/vue/User/Info.vue
@@ -97,7 +97,12 @@
                                     <tbody>
                                         <tr v-for="sku in skus" :id="'s' + sku.id" :key="sku.id">
                                             <td class="selection">
-                                                <input type="checkbox" :value="sku.id" :disabled="sku.readonly" :checked="sku.enabled">
+                                                <input type="checkbox" @input="onInputSku"
+                                                       :value="sku.id"
+                                                       :disabled="sku.readonly"
+                                                       :checked="sku.enabled"
+                                                       :dusk="'sku-input-' + sku.title"
+                                                >
                                             </td>
                                             <td class="name">
                                                 <span class="name">{{ sku.name }}</span>
@@ -235,6 +240,65 @@
                         }
                     })
             },
+            onInputSku(e) {
+                let input = e.target
+                let sku = this.findSku(input.value)
+                let required = []
+
+                // We use 'readonly', not 'disabled', because we might want to handle
+                // input events. For example to display an error when someone clicks
+                // the locked input
+                if (input.readOnly) {
+                    input.checked = !input.checked
+                    // TODO: Display an alert explaining why it's locked
+                    return
+                }
+
+                // TODO: Following code might not work if we change definition of forbidden/required
+                //       or we just need more sophisticated SKU dependency rules
+
+                if (input.checked) {
+                    // Check if a required SKU is selected, alert the user if not
+                    (sku.required || []).forEach(title => {
+                        this.skus.forEach(item => {
+                            let checkbox
+                            if (item.handler == title && (checkbox = $('#s' + item.id).find('input[type=checkbox]')[0])) {
+                                if (!checkbox.checked) {
+                                    required.push(item.name)
+                                }
+                            }
+                        })
+                    })
+
+                    if (required.length) {
+                        input.checked = false
+                        return alert(sku.name + ' requires ' + required.join(', ') + '.')
+                    }
+                } else {
+                    // Uncheck all dependent SKUs, e.g. when unchecking Groupware we also uncheck Activesync
+                    // TODO: Should we display an alert instead?
+                    this.skus.forEach(item => {
+                        if (item.required && item.required.indexOf(sku.handler) > -1) {
+                            $('#s' + item.id).find('input[type=checkbox]').prop('checked', false)
+                        }
+                    })
+                }
+
+                // Uncheck+lock/unlock conflicting SKUs
+                (sku.forbidden || []).forEach(title => {
+                    this.skus.forEach(item => {
+                        let checkbox
+                        if (item.handler == title && (checkbox = $('#s' + item.id).find('input[type=checkbox]')[0])) {
+                            if (input.checked) {
+                                checkbox.checked = false
+                                checkbox.readOnly = true
+                            } else {
+                                checkbox.readOnly = false
+                            }
+                        }
+                    })
+                })
+            },
             selectPackage(e) {
                 // Make sure there always is only one package selected
                 $('#user-packages input').prop('checked', false)
@@ -245,19 +309,20 @@
                 let value = input.val()
                 let record = input.parents('tr').first()
                 let sku_id = record.find('input[type=checkbox]').val()
-                let sku, i
-
-                for (i = 0; i < this.skus.length; i++) {
-                    if (this.skus[i].id == sku_id) {
-                        sku = this.skus[i];
-                    }
-                }
+                let sku = this.findSku(sku_id)
 
                 // Update the label
                 input.prev().text(value + ' ' + sku.range.unit)
 
                 // Update the price
                 record.find('.price').text(this.$root.price(sku.cost * (value - sku.units_free)) + '/month')
+            },
+            findSku(id) {
+                for (let i = 0; i < this.skus.length; i++) {
+                    if (this.skus[i].id == id) {
+                        return this.skus[i];
+                    }
+                }
             }
         }
     }
diff --git a/src/tests/Browser.php b/src/tests/Browser.php
--- a/src/tests/Browser.php
+++ b/src/tests/Browser.php
@@ -70,6 +70,32 @@
     }
 
     /**
+     * Assert that the given element is readonly
+     */
+    public function assertReadonly($selector)
+    {
+        $element = $this->resolver->findOrFail($selector);
+        $value = $element->getAttribute('readonly');
+
+        Assert::assertTrue($value == 'true', "Element [$selector] is not readonly");
+
+        return $this;
+    }
+
+    /**
+     * Assert that the given element is not readonly
+     */
+    public function assertNotReadonly($selector)
+    {
+        $element = $this->resolver->findOrFail($selector);
+        $value = $element->getAttribute('readonly');
+
+        Assert::assertTrue($value != 'true', "Element [$selector] is not readonly");
+
+        return $this;
+    }
+
+    /**
      * Assert that the given element contains specified text,
      * no matter it's displayed or not.
      */
diff --git a/src/tests/Browser/UsersTest.php b/src/tests/Browser/UsersTest.php
--- a/src/tests/Browser/UsersTest.php
+++ b/src/tests/Browser/UsersTest.php
@@ -39,13 +39,7 @@
         UserAlias::where('user_id', $john->id)
             ->where('alias', 'john.test@kolab.org')->delete();
 
-        Sku::where('title', 'test')->delete();
-        $storage = Sku::where('title', 'storage')->first();
-        Entitlement::where([
-                ['sku_id', $storage->id],
-                ['entitleable_id', $john->id],
-                ['cost', 25]
-            ])->delete();
+        Entitlement::where('entitleable_id', $john->id)->whereIn('cost', [25, 100])->delete();
     }
 
     /**
@@ -60,13 +54,7 @@
         UserAlias::where('user_id', $john->id)
             ->where('alias', 'john.test@kolab.org')->delete();
 
-        Sku::where('title', 'test')->delete();
-        $storage = Sku::where('title', 'storage')->first();
-        Entitlement::where([
-                ['sku_id', $storage->id],
-                ['entitleable_id', $john->id],
-                ['cost', 25]
-            ])->delete();
+        Entitlement::where('entitleable_id', $john->id)->whereIn('cost', [25, 100])->delete();
 
         parent::tearDown();
     }
@@ -127,17 +115,6 @@
      */
     public function testInfo(): void
     {
-        Sku::create([
-                'title' => 'test',
-                'name' => 'Test SKU',
-                'description' => 'The SKU for testing',
-                'cost' => 666,
-                'units_free' => 0,
-                'period' => 'monthly',
-                'handler_class' => 'App\Handlers\Groupware',
-                'active' => true,
-        ]);
-
         $this->browse(function (Browser $browser) {
             $browser->on(new UserList())
                 ->click('@table tr:nth-child(2) a')
@@ -241,48 +218,57 @@
                 $browser->assertSeeIn('div.row:nth-child(8) label', 'Subscriptions')
                     ->assertVisible('@skus.row:nth-child(8)')
                     ->with('@skus', function ($browser) {
-                        $browser->assertElementsCount('tbody tr', 4)
-                            // groupware SKU
-                            ->assertSeeIn('tbody tr:nth-child(1) td.name', 'Groupware Features')
-                            ->assertSeeIn('tbody tr:nth-child(1) td.price', '5,55 CHF/month')
+                        $browser->assertElementsCount('tbody tr', 5)
+                            // Mailbox SKU
+                            ->assertSeeIn('tbody tr:nth-child(1) td.name', 'User Mailbox')
+                            ->assertSeeIn('tbody tr:nth-child(1) td.price', '4,44 CHF/month')
                             ->assertChecked('tbody tr:nth-child(1) td.selection input')
-                            ->assertEnabled('tbody tr:nth-child(1) td.selection input')
+                            ->assertDisabled('tbody tr:nth-child(1) td.selection input')
                             ->assertTip(
                                 'tbody tr:nth-child(1) td.buttons button',
-                                'Groupware functions like Calendar, Tasks, Notes, etc.'
+                                'Just a mailbox'
                             )
-                            // Mailbox SKU
-                            ->assertSeeIn('tbody tr:nth-child(2) td.name', 'User Mailbox')
-                            ->assertSeeIn('tbody tr:nth-child(2) td.price', '4,44 CHF/month')
+                            // Storage SKU
+                            ->assertSeeIn('tbody tr:nth-child(2) td.name', 'Storage Quota')
+                            ->assertSeeIn('tr:nth-child(2) td.price', '0,00 CHF/month')
                             ->assertChecked('tbody tr:nth-child(2) td.selection input')
                             ->assertDisabled('tbody tr:nth-child(2) td.selection input')
                             ->assertTip(
                                 'tbody tr:nth-child(2) td.buttons button',
-                                'Just a mailbox'
+                                'Some wiggle room'
                             )
-                            // Storage SKU
-                            ->assertSeeIn('tbody tr:nth-child(3) td.name', 'Storage Quota')
-                            ->assertSeeIn('tr:nth-child(3) td.price', '0,00 CHF/month')
+                            ->with(new QuotaInput('tbody tr:nth-child(2) .range-input'), function ($browser) {
+                                $browser->assertQuotaValue(2)->setQuotaValue(3);
+                            })
+                            ->assertSeeIn('tr:nth-child(2) td.price', '0,25 CHF/month')
+                            // groupware SKU
+                            ->assertSeeIn('tbody tr:nth-child(3) td.name', 'Groupware Features')
+                            ->assertSeeIn('tbody tr:nth-child(3) td.price', '5,55 CHF/month')
                             ->assertChecked('tbody tr:nth-child(3) td.selection input')
-                            ->assertDisabled('tbody tr:nth-child(3) td.selection input')
+                            ->assertEnabled('tbody tr:nth-child(3) td.selection input')
                             ->assertTip(
                                 'tbody tr:nth-child(3) td.buttons button',
-                                'Some wiggle room'
+                                'Groupware functions like Calendar, Tasks, Notes, etc.'
                             )
-                            ->with(new QuotaInput('tbody tr:nth-child(3) .range-input'), function ($browser) {
-                                $browser->assertQuotaValue(2)->setQuotaValue(3);
-                            })
-                            ->assertSeeIn('tr:nth-child(3) td.price', '0,25 CHF/month')
-                            // Test SKU
-                            ->assertSeeIn('tbody tr:nth-child(4) td.name', 'Test SKU')
-                            ->assertSeeIn('tbody tr:nth-child(4) td.price', '6,66 CHF/month')
+                            // 2FA SKU
+                            ->assertSeeIn('tbody tr:nth-child(4) td.name', '2-Factor Authentication')
+                            ->assertSeeIn('tbody tr:nth-child(4) td.price', '0,00 CHF/month')
                             ->assertNotChecked('tbody tr:nth-child(4) td.selection input')
                             ->assertEnabled('tbody tr:nth-child(4) td.selection input')
                             ->assertTip(
                                 'tbody tr:nth-child(4) td.buttons button',
-                                'The SKU for testing'
+                                'Two factor authentication for webmail and administration panel'
                             )
-                            ->click('tbody tr:nth-child(4) td.selection input');
+                            // ActiveSync SKU
+                            ->assertSeeIn('tbody tr:nth-child(5) td.name', 'Activesync')
+                            ->assertSeeIn('tbody tr:nth-child(5) td.price', '1,00 CHF/month')
+                            ->assertNotChecked('tbody tr:nth-child(5) td.selection input')
+                            ->assertEnabled('tbody tr:nth-child(5) td.selection input')
+                            ->assertTip(
+                                'tbody tr:nth-child(5) td.buttons button',
+                                'Mobile synchronization'
+                            )
+                            ->click('tbody tr:nth-child(5) td.selection input');
                     })
                     ->click('button[type=submit]');
             })
@@ -292,7 +278,34 @@
                     ->closeToast();
             });
 
-            $this->assertUserEntitlements($john, ['groupware', 'mailbox', 'storage', 'storage', 'storage', 'test']);
+            $expected = ['activesync', 'groupware', 'mailbox', 'storage', 'storage', 'storage'];
+            $this->assertUserEntitlements($john, $expected);
+
+            // Test subscriptions interaction
+            $browser->with('@form', function (Browser $browser) {
+                $browser->with('@skus', function ($browser) {
+                    // Uncheck 'groupware', expect activesync unchecked
+                    $browser->click('@sku-input-groupware')
+                        ->assertNotChecked('@sku-input-groupware')
+                        ->assertNotChecked('@sku-input-activesync')
+                        ->assertEnabled('@sku-input-activesync')
+                        ->assertNotReadonly('@sku-input-activesync')
+                        // Check 'activesync', expect an alert
+                        ->click('@sku-input-activesync')
+                        ->assertDialogOpened('Activesync requires Groupware Features.')
+                        ->acceptDialog()
+                        ->assertNotChecked('@sku-input-activesync')
+                        // Check '2FA', expect 'activesync' unchecked and readonly
+                        ->click('@sku-input-2fa')
+                        ->assertChecked('@sku-input-2fa')
+                        ->assertNotChecked('@sku-input-activesync')
+                        ->assertReadonly('@sku-input-activesync')
+                        // Uncheck '2FA'
+                        ->click('@sku-input-2fa')
+                        ->assertNotChecked('@sku-input-2fa')
+                        ->assertNotReadonly('@sku-input-activesync');
+                });
+            });
         });
     }
 
diff --git a/src/tests/Feature/Controller/SkusTest.php b/src/tests/Feature/Controller/SkusTest.php
--- a/src/tests/Feature/Controller/SkusTest.php
+++ b/src/tests/Feature/Controller/SkusTest.php
@@ -18,25 +18,26 @@
         $response->assertStatus(401);
 
         $user = $this->getTestUser('john@kolab.org');
-        $domain_sku = Sku::where('title', 'domain')->first();
+        $sku = Sku::where('title', 'mailbox')->first();
 
         $response = $this->actingAs($user)->get("api/v4/skus");
         $response->assertStatus(200);
 
         $json = $response->json();
 
-        $this->assertCount(7, $json);
+        $this->assertCount(9, $json);
 
-        $this->assertSame($domain_sku->id, $json[0]['id']);
-        $this->assertSame($domain_sku->title, $json[0]['title']);
-        $this->assertSame($domain_sku->name, $json[0]['name']);
-        $this->assertSame($domain_sku->description, $json[0]['description']);
-        $this->assertSame($domain_sku->cost, $json[0]['cost']);
-        $this->assertSame($domain_sku->units_free, $json[0]['units_free']);
-        $this->assertSame($domain_sku->period, $json[0]['period']);
-        $this->assertSame($domain_sku->active, $json[0]['active']);
-        $this->assertSame('domain', $json[0]['type']);
-        $this->assertSame('domain', $json[0]['handler']);
+        $this->assertSame(100, $json[0]['prio']);
+        $this->assertSame($sku->id, $json[0]['id']);
+        $this->assertSame($sku->title, $json[0]['title']);
+        $this->assertSame($sku->name, $json[0]['name']);
+        $this->assertSame($sku->description, $json[0]['description']);
+        $this->assertSame($sku->cost, $json[0]['cost']);
+        $this->assertSame($sku->units_free, $json[0]['units_free']);
+        $this->assertSame($sku->period, $json[0]['period']);
+        $this->assertSame($sku->active, $json[0]['active']);
+        $this->assertSame('user', $json[0]['type']);
+        $this->assertSame('mailbox', $json[0]['handler']);
     }
 
     /**