diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bb6f3a28..6f104ffb 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -3,7 +3,7 @@ image: registry.gitlab.com/bitfireat/davdroid:latest
 before_script:
   - git submodule update --init --recursive
   - export GRADLE_USER_HOME=`pwd`/.gradle; chmod +x gradlew
-  - emulator64-x86 @test -verbose -no-audio -no-window -gpu off -wipe-data & wait-for-emulator.sh
+  - (cd /sdk/emulator; ./emulator @test -no-audio -no-window & wait-for-emulator.sh)
   - wget -q https://f-droid.org/repo/org.dmfs.tasks_481.apk && adb install org.dmfs.tasks_481.apk
 
 cache:
diff --git a/app/build.gradle b/app/build.gradle
index 52b85d98..fb360e03 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -12,7 +12,7 @@ apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion 26
-    buildToolsVersion '26.0.1'
+    buildToolsVersion '26.0.2'
 
     defaultConfig {
         applicationId "at.bitfire.davdroid"
@@ -25,6 +25,8 @@ android {
         targetSdkVersion 25
     }
 
+    flavorDimensions "type"
+
     productFlavors {
         standard {
             versionName "1.9.1-ose"
@@ -72,10 +74,10 @@ dependencies {
 
     compile "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
 
-    compile 'com.android.support:appcompat-v7:26.0.1'
-    compile 'com.android.support:cardview-v7:26.0.1'
-    compile 'com.android.support:design:26.0.1'
-    compile 'com.android.support:preference-v14:26.0.1'
+    compile 'com.android.support:appcompat-v7:26.1.0'
+    compile 'com.android.support:cardview-v7:26.1.0'
+    compile 'com.android.support:design:26.1.0'
+    compile 'com.android.support:preference-v14:26.1.0'
 
     compile 'com.github.yukuku:ambilwarna:2.0.1'
 
diff --git a/build.gradle b/build.gradle
index e4f88779..4bd2da8a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -12,9 +12,12 @@ buildscript {
 
     repositories {
         jcenter()
+        maven {
+            url "https://maven.google.com"
+        }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.3'
+        classpath 'com.android.tools.build:gradle:3.0.0'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
diff --git a/cert4android b/cert4android
index f93031e8..169d99c7 160000
--- a/cert4android
+++ b/cert4android
@@ -1 +1 @@
-Subproject commit f93031e8e3cc82d5eae54da5b768f6877136f01d
+Subproject commit 169d99c71ae4bd2d59dfeaed267dae4f75d57cbc
diff --git a/dav4android b/dav4android
index 07df1dc2..7054c635 160000
--- a/dav4android
+++ b/dav4android
@@ -1 +1 @@
-Subproject commit 07df1dc2e922ddf8c6428e8563b70a3fb796677b
+Subproject commit 7054c635a2591d4a859d5f7b51f4cb7135bbcd1c
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 2bc9ba93..1f551caf 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.0.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.2.1-bin.zip
diff --git a/ical4android b/ical4android
index 83dab17f..d1416a4a 160000
--- a/ical4android
+++ b/ical4android
@@ -1 +1 @@
-Subproject commit 83dab17f03ee0d82f28445ba07e805fbe2ded552
+Subproject commit d1416a4a25c0cd0ab3171169bfb0c8642aeb590b
diff --git a/vcard4android b/vcard4android
index 9f5a0b3b..48818380 160000
--- a/vcard4android
+++ b/vcard4android
@@ -1 +1 @@
-Subproject commit 9f5a0b3bf7e0fbb08bb595c166dc995b27929c18
+Subproject commit 48818380683c56ba36aff1809ae0b56e267dccb7