diff --git a/build.gradle b/build.gradle
index 512fdbfac..65226215b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -13,7 +13,7 @@ project.ext {
     preDexLibs = !project.hasProperty('disablePreDex')
     testCoverage = project.hasProperty('testCoverage')
 
-    compileSdkVersion = 22
+    compileSdkVersion = 23
     buildToolsVersion = '23.0.1'
 }
 
diff --git a/k9mail-library/build.gradle b/k9mail-library/build.gradle
index f3550c278..d002e67a0 100644
--- a/k9mail-library/build.gradle
+++ b/k9mail-library/build.gradle
@@ -31,6 +31,9 @@ android {
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
 
+    // for using Apache HTTP Client
+    useLibrary 'org.apache.http.legacy'
+
     buildTypes {
         debug {
             testCoverageEnabled rootProject.testCoverage
diff --git a/k9mail/src/main/java/com/fsck/k9/helper/MergeCursor.java b/k9mail/src/main/java/com/fsck/k9/helper/MergeCursor.java
index a69ebf5bc..96dff9ccb 100644
--- a/k9mail/src/main/java/com/fsck/k9/helper/MergeCursor.java
+++ b/k9mail/src/main/java/com/fsck/k9/helper/MergeCursor.java
@@ -19,12 +19,14 @@ package com.fsck.k9.helper;
 
 import java.util.Comparator;
 
+import android.annotation.TargetApi;
 import android.content.ContentResolver;
 import android.database.CharArrayBuffer;
 import android.database.ContentObserver;
 import android.database.Cursor;
 import android.database.DataSetObserver;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
 
 
@@ -213,6 +215,12 @@ public class MergeCursor implements Cursor {
         return mActiveCursor.getWantsAllOnMoveCalls();
     }
 
+    @TargetApi(Build.VERSION_CODES.M)
+    @Override
+    public void setExtras(Bundle extras) {
+        mActiveCursor.setExtras(extras);
+    }
+
     @Override
     public boolean isAfterLast() {
         int count = getCount();
diff --git a/k9mail/src/main/java/com/fsck/k9/provider/MessageProvider.java b/k9mail/src/main/java/com/fsck/k9/provider/MessageProvider.java
index fec2b4f5f..b54abf98c 100644
--- a/k9mail/src/main/java/com/fsck/k9/provider/MessageProvider.java
+++ b/k9mail/src/main/java/com/fsck/k9/provider/MessageProvider.java
@@ -1,5 +1,6 @@
 package com.fsck.k9.provider;
 
+import android.annotation.TargetApi;
 import android.app.Application;
 import android.content.ContentProvider;
 import android.content.ContentResolver;
@@ -15,6 +16,7 @@ import android.database.DataSetObserver;
 import android.database.MatrixCursor;
 import android.net.Uri;
 import android.os.Binder;
+import android.os.Build;
 import android.os.Bundle;
 import android.provider.BaseColumns;
 import android.util.Log;
@@ -715,6 +717,12 @@ public class MessageProvider extends ContentProvider {
             return mCursor.getWantsAllOnMoveCalls();
         }
 
+        @TargetApi(Build.VERSION_CODES.M)
+        @Override
+        public void setExtras(Bundle extras) {
+            mCursor.setExtras(extras);
+        }
+
         @Override
         public boolean isAfterLast() {
             checkClosed();
diff --git a/plugins/Android-PullToRefresh/library/src/com/handmark/pulltorefresh/library/PullToRefreshWebView.java b/plugins/Android-PullToRefresh/library/src/com/handmark/pulltorefresh/library/PullToRefreshWebView.java
index 3f873de08..d1abc5423 100644
--- a/plugins/Android-PullToRefresh/library/src/com/handmark/pulltorefresh/library/PullToRefreshWebView.java
+++ b/plugins/Android-PullToRefresh/library/src/com/handmark/pulltorefresh/library/PullToRefreshWebView.java
@@ -112,7 +112,7 @@ public class PullToRefreshWebView extends PullToRefreshBase<WebView> {
 
 	@Override
 	protected boolean isReadyForPullEnd() {
-		float exactContentHeight = FloatMath.floor(mRefreshableView.getContentHeight() * mRefreshableView.getScale());
+		double exactContentHeight = Math.floor(mRefreshableView.getContentHeight() * mRefreshableView.getScale());
 		return mRefreshableView.getScrollY() >= (exactContentHeight - mRefreshableView.getHeight());
 	}
 
@@ -158,7 +158,7 @@ public class PullToRefreshWebView extends PullToRefreshBase<WebView> {
 		}
 
 		private int getScrollRange() {
-			return (int) Math.max(0, FloatMath.floor(mRefreshableView.getContentHeight() * mRefreshableView.getScale())
+			return (int) Math.max(0, Math.floor(mRefreshableView.getContentHeight() * mRefreshableView.getScale())
 					- (getHeight() - getPaddingBottom() - getPaddingTop()));
 		}
 	}