diff --git a/app/build.gradle b/app/build.gradle
index 1ea563512..ebd454a36 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -14,16 +14,16 @@ def getVersionName = { ->
 }
 
 dependencies {
-    compile "com.android.support:support-v4:25.3.1"
-    compile "com.android.support:appcompat-v7:25.3.1"
-    compile "com.android.support:gridlayout-v7:25.3.1"
-    compile "com.android.support:support-annotations:25.3.1"
-    compile "com.android.support:recyclerview-v7:25.3.1"
-    compile "com.android.support:cardview-v7:25.3.1"
-    compile "com.android.support:design:25.3.1"
-    compile "com.android.support:support-vector-drawable:25.3.1"
-    compile 'com.android.support.constraint:constraint-layout:1.0.2'
-    compile "com.android.support:palette-v7:25.3.1"
+    compile "com.android.support:support-v4:27.1.1"
+    compile "com.android.support:appcompat-v7:27.1.1"
+    compile "com.android.support:gridlayout-v7:27.1.1"
+    compile "com.android.support:support-annotations:27.1.1"
+    compile "com.android.support:recyclerview-v7:27.1.1"
+    compile "com.android.support:cardview-v7:27.1.1"
+    compile "com.android.support:design:27.1.1"
+    compile "com.android.support:support-vector-drawable:27.1.1"
+    compile 'com.android.support.constraint:constraint-layout:1.1.0'
+    compile "com.android.support:palette-v7:27.1.1"
 
     compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'
     compile 'com.google.zxing:core:3.3.2'
@@ -85,28 +85,34 @@ if (!hasProperty('sourceDeps')) {
     // generate using: `gradle -q calculateChecksums | sort -V`
     dependencyVerification {
         verify = [
+                'android.arch.core:common:d34824b794bc92ff8f647a9bb13a7c73de920de5b47075b5d2c4f0770e9b8bfd',
+                'android.arch.core:runtime:83400f7575bcfb8a2eeec64e05590f037bfaed1e56aa3a4214d20e55878445e3',
+                'android.arch.lifecycle:common:614e31cfd33255dc4d5f5d8e62cfa6be2fbbc2a35643a79dc3ed008004c30807',
+                'android.arch.lifecycle:livedata-core:14e57ff8ffb65a80c7e72d91f2076acccdaf2970f234c6261e03a6127eb5206b',
+                'android.arch.lifecycle:runtime:094fd793924dd6a5136753e599ac8174a8147f4a401386b694ba7d818c223e2e',
+                'android.arch.lifecycle:viewmodel:6407c93a5ea9850661dca42a0068d6f3deccefd7228ee69bae1c35d70cbc2557',
                 'cc.mvdan.accesspoint:library:0837b38adb48b66bb1385adb6ade8ecce7002ad815c55abf13517c82193458ea',
                 'ch.acra:acra:d2762968c448757a7d6acc9f141881d9632f664988e9723ece33b5f7c79f3bc9',
                 'commons-io:commons-io:a10418348d234968600ccb1d988efcbbd08716e1d96936ccc1880e7d22513474',
                 'commons-net:commons-net:c25b0da668b3c5649f002d504def22d1b4cb30d206f05428d2fe168fa1a901c2',
-                'com.android.support.constraint:constraint-layout-solver:8c62525a9bc5cff5633a96cb9b32fffeccaf41b8841aa87fc22607070dea9b8d',
-                'com.android.support.constraint:constraint-layout:b0c688cc2b7172608f8153a689d746da40f71e52d7e2fe2bfd9df2f92db77085',
-                'com.android.support:animated-vector-drawable:4bc46edf1946b32d518b41416d1734e915e0cbb28021de3b340527419b070691',
-                'com.android.support:appcompat-v7:ac1ebbc46589195dda3e0b1becfe410bafd75bdf3edd1cd9acf04850f3895830',
-                'com.android.support:cardview-v7:defc17032ffa600a82e1c7d96bb574aa5ed64e2b57e28414a245da7d6db0c666',
-                'com.android.support:design:a3e83064fe99d0a4369f9b46d8bfbe77d0c3022fffdee4be3ac3857b87cc89e3',
-                'com.android.support:gridlayout-v7:de87a59472f19eb05429faf6b2683a09dd6995f5db562d3daf6033297c312388',
-                'com.android.support:palette-v7:956276da2ed8b6c087c431da807a496f4908061c9c64d4c9f7b42c626d633662',
-                'com.android.support:recyclerview-v7:375974a8724e359d97d77fa8522c614f813a3ac4583c1807f154a3f9a054b0a1',
-                'com.android.support:support-annotations:aedf76962584adfaed2bd3fcaa22406461c4310237fc27e301128edaa2dba2fa',
-                'com.android.support:support-compat:e02d781268dc60aab6638d8dc20156ea11ca20b962d294b85e6f1e8418cabfa7',
-                'com.android.support:support-core-ui:6182278a6653e6c111c888963626cbb16f2d0022571cb239760475119e0b92a8',
-                'com.android.support:support-core-utils:32fac02eb2c20a77fa3e3bc3ede62392a19613f72b8f8e10f5dfa84bb4c89ea1',
-                'com.android.support:support-fragment:541d6393c1e024453aca2a14f31bea0c7270ff4e2a02783f3528aa426367444d',
-                'com.android.support:support-media-compat:cbed07d07e0e84fdb4b75712f5fd946229a8af155933c9a92e41db64d00791e0',
-                'com.android.support:support-v4:07d389154bcf73b47e514964df1578136b26cba78257b8a577a3ccb54beff0ae',
-                'com.android.support:support-vector-drawable:13728f337f36d1c02d52198a6c20724edb447a0875454d829f95cb9eb4aa293b',
-                'com.android.support:transition:36c688825a8c0e6e879e18886de83dc90673322822d5b606ee302f70fb558e16',
+                'com.android.support.constraint:constraint-layout-solver:fcb4c7d705754ca3d69b1b2c3caf445a425599fda8caabbcf855d98ea0663e4e',
+                'com.android.support.constraint:constraint-layout:d490188709b7bb2f11609beadd7e5eb7538892f308828ec3ff261a74e6ecf47e',
+                'com.android.support:animated-vector-drawable:59670473f6e98fda792f7bef25dd7292b0a3106031c7a5e30eb020bf26f077bd',
+                'com.android.support:appcompat-v7:0c7808fbbc5838d831e32e3c0a6f84e1f2c981deb8f11e010650f2b57923a335',
+                'com.android.support:cardview-v7:8ed955dd037d82a7b4bbcaedb4f896523c3e4c1bf3ca698ce807c350767a2886',
+                'com.android.support:design:7225973f7ee03765008a9c2f17a40b154c6885169fef022276e811c926a2202c',
+                'com.android.support:gridlayout-v7:2f5af33c4be1d3e4e3fa999323265718ac1a4c81df4c0373d6ce8901613b1671',
+                'com.android.support:palette-v7:6d24037fb375c7884f878edeb88c812b87a05c69221513507ecea21c257d6314',
+                'com.android.support:recyclerview-v7:d735e4727878e99ef3980c10d15dc3468462fd509d4fb60cb8bd20b0f735085c',
+                'com.android.support:support-annotations:3365960206c3d2b09e845f555e7f88f8effc8d2f00b369e66c4be384029299cf',
+                'com.android.support:support-compat:880ce01ff5be42b233ff8ec0c61cefb7dc3dc9500fea9e24423214813ac27ea2',
+                'com.android.support:support-core-ui:a3ae20e6d5dffba69ac97b99846d2738003af8563843d5f3c9dc4c35b4804241',
+                'com.android.support:support-core-utils:61036832c54e8701aae954fc3bf96d1d80bf8d9dd531bff77d72def456ba087a',
+                'com.android.support:support-fragment:ec72d6ac36a1a0e6523bbddba33d73ffad070b9b3dd246cc44d8727a41ddb5e6',
+                'com.android.support:support-media-compat:55e9837dda88b74a8c812c63a78c63fd83c6c039a8c22d318492663a493585eb',
+                'com.android.support:support-v4:4f41dfc3e89f2738e45c86264a85c0934d055ee8ebe2020e23c97f303b80a48b',
+                'com.android.support:support-vector-drawable:1c0f421114cf4627cf208776d6eb4f76340c78b7e96fe6e12b3e6eb950caf1b9',
+                'com.android.support:transition:c0765b2f3c78696567ec5b3f519d22da1e3df11ac994625adf4bb4dc571caacc',
                 'com.fasterxml.jackson.core:jackson-annotations:6b7802f6c22c09c4a92a2ebeb76e755c3c0a58dfbf419835fae470d89e469b86',
                 'com.fasterxml.jackson.core:jackson-core:256ff34118ab292d1b4f3ee4d2c3e5e5f0f609d8e07c57e8ad1f51c46d4fbb46',
                 'com.fasterxml.jackson.core:jackson-databind:4f74337b6d18664be0f5b15c6664b17aa3972c9c175092328b139b894ff66f19',
@@ -165,8 +171,8 @@ def isCi = "true".equals(System.getenv("CI"))
 def preDexEnabled = "true".equals(System.getProperty("pre-dex", "true"))
 
 android {
-    compileSdkVersion 24
-    buildToolsVersion '25.0.3'
+    compileSdkVersion 27
+    buildToolsVersion '27.0.3'
 
     buildTypes {
         // use proguard on debug too since we have unknowingly broken
diff --git a/app/lint.xml b/app/lint.xml
index 9b3dccf85..5a30e2915 100644
--- a/app/lint.xml
+++ b/app/lint.xml
@@ -31,6 +31,10 @@
         <ignore path="src/main/java/org/fdroid/fdroid/installer/ApkFileProvider.java"/>
     </issue>
 
+    <issue id="ProtectedPermissions" severity="error">
+        <ignore path="src/main/AndroidManifest.xml"/>
+    </issue>
+
     <!-- these should be fixed, but it'll be a chunk of work -->
     <issue id="SetTextI18n" severity="error">
         <ignore path="src/main/java/org/fdroid/fdroid/views/AppDetailsRecyclerViewAdapter.java"/>
diff --git a/app/src/main/java/org/fdroid/fdroid/NfcNotEnabledActivity.java b/app/src/main/java/org/fdroid/fdroid/NfcNotEnabledActivity.java
index e6f49ad48..3961ff65c 100644
--- a/app/src/main/java/org/fdroid/fdroid/NfcNotEnabledActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/NfcNotEnabledActivity.java
@@ -6,10 +6,10 @@ import android.nfc.NfcAdapter;
 import android.os.Build;
 import android.os.Bundle;
 import android.provider.Settings;
-import android.support.v7.app.ActionBarActivity;
+import android.support.v7.app.AppCompatActivity;
 
 // aka Android 4.0 aka Ice Cream Sandwich
-public class NfcNotEnabledActivity extends ActionBarActivity {
+public class NfcNotEnabledActivity extends AppCompatActivity {
 
     /*
      * ACTION_NFC_SETTINGS was added in 4.1 aka Jelly Bean MR1 as a
diff --git a/app/src/main/java/org/fdroid/fdroid/views/RepoDetailsActivity.java b/app/src/main/java/org/fdroid/fdroid/views/RepoDetailsActivity.java
index 546dcce4e..7af876e16 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/RepoDetailsActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/RepoDetailsActivity.java
@@ -15,8 +15,8 @@ import android.os.Bundle;
 import android.os.Parcelable;
 import android.support.v4.app.NavUtils;
 import android.support.v4.content.LocalBroadcastManager;
-import android.support.v7.app.ActionBarActivity;
 import android.support.v7.app.AlertDialog;
+import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
 import android.text.TextUtils;
 import android.text.format.DateUtils;
@@ -40,7 +40,7 @@ import org.fdroid.fdroid.data.Schema.RepoTable;
 
 import java.util.Locale;
 
-public class RepoDetailsActivity extends ActionBarActivity {
+public class RepoDetailsActivity extends AppCompatActivity {
     private static final String TAG = "RepoDetailsActivity";
 
     public static final String ARG_REPO_ID = "repo_id";