diff --git a/.travis.yml b/.travis.yml
index 4c6092d..1e0914f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,21 +1,25 @@
-sudo: false
+sudo: required
 language: java
 jdk:
 - oraclejdk8
-- oraclejdk7
-- openjdk6
+- oraclejdk9
 - openjdk7
+- openjdk8
+before_install:
+  # OpenJDK 7 does not support HTTPS using Elliptic Curves, but the Gradle
+  # server use them. Therefore, we manually disable them to enable communication.
+  - sudo sed -i 's/^jdk.certpath.disabledAlgorithms=.*/jdk.certpath.disabledAlgorithms=MD2, MD5, RSA keySize < 1024, ECDSA/' /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/security/java.security || true
 deploy:
   - provider: script
     script: ./deploy-gh-pages.sh
     on:
       branch: master
-      jdk: openjdk7
+      jdk: openjdk8
   - provider: script
     script: ./deploy-bintray.sh
     on:
       tags: true
-      jdk: openjdk6
+      jdk: openjdk8
 
 env:
   global:
diff --git a/build.gradle b/build.gradle
index a2a1f4d..027c102 100644
--- a/build.gradle
+++ b/build.gradle
@@ -9,10 +9,15 @@ allprojects {
     }
 }
 
+// We compile the library using Java 1.6 compatibility
+// in order to ensure interoperability with older Android platforms.
+sourceCompatibility = 1.6
+targetCompatibility = 1.6
+
 dependencies {
     compile 'org.jetbrains:annotations:13.0'
     testCompile 'junit:junit:4.12'
-    testCompile 'org.mock-server:mockserver-netty:3.9.17'
+    testCompile 'org.mock-server:mockserver-netty:5.2.2'
 }
 
 task sourcesJar(type: Jar, dependsOn: classes) {
@@ -25,38 +30,40 @@ task javadocJar(type: Jar, dependsOn: javadoc) {
     from javadoc.destinationDir
 }
 
-task createPom << {
-    pom {
-        project {
-            groupId 'io.tus.java.client'
-            artifactId 'tus-java-client'
-            name 'tus-java-client'
-            version project.getProperties().get('pomVersion')
-            packaging 'pom'
-            description 'Java client for tus, the resumable file uploading protocol.'
-            url 'http://tus.io'
-
-            scm {
-                url 'https://github.com/tus/tus-java-client'
-                connection 'https://github.com/tus/tus-java-client'
-                developerConnection 'https://github.com/tus/tus-java-client'
-            }
+task createPom {
+    doLast {
+        pom {
+            project {
+                groupId 'io.tus.java.client'
+                artifactId 'tus-java-client'
+                name 'tus-java-client'
+                version project.getProperties().get('pomVersion')
+                packaging 'pom'
+                description 'Java client for tus, the resumable file uploading protocol.'
+                url 'http://tus.io'
 
-            developers {
-                developer {
-                    id 'acconut'
-                    name 'Marius Kleidl'
-                    email 'maerious@gmail.com'
+                scm {
+                    url 'https://github.com/tus/tus-java-client'
+                    connection 'https://github.com/tus/tus-java-client'
+                    developerConnection 'https://github.com/tus/tus-java-client'
                 }
-            }
 
-            inceptionYear '2015'
-            licenses {
-                license {
-                    name 'The MIT License (MIT)'
-                    url 'http://opensource.org/licenses/MIT'
+                developers {
+                    developer {
+                        id 'acconut'
+                        name 'Marius Kleidl'
+                        email 'maerious@gmail.com'
+                    }
+                }
+
+                inceptionYear '2015'
+                licenses {
+                    license {
+                        name 'The MIT License (MIT)'
+                        url 'http://opensource.org/licenses/MIT'
+                    }
                 }
             }
-        }
-    }.writeTo("build/libs/pom.xml")
+        }.writeTo("build/libs/pom.xml")
+    }
 }
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 0087cd3..01b8bf6 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 7e9325e..933b647 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,5 @@
-#Thu Jul 16 22:37:16 CEST 2015
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-1.12-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip
diff --git a/gradlew b/gradlew
index 91a7e26..cccdd3d 100755
--- a/gradlew
+++ b/gradlew
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/usr/bin/env sh
 
 ##############################################################################
 ##
@@ -6,20 +6,38 @@
 ##
 ##############################################################################
 
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
 
 APP_NAME="Gradle"
 APP_BASE_NAME=`basename "$0"`
 
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
 
-warn ( ) {
+warn () {
     echo "$*"
 }
 
-die ( ) {
+die () {
     echo
     echo "$*"
     echo
@@ -30,6 +48,7 @@ die ( ) {
 cygwin=false
 msys=false
 darwin=false
+nonstop=false
 case "`uname`" in
   CYGWIN* )
     cygwin=true
@@ -40,31 +59,11 @@ case "`uname`" in
   MINGW* )
     msys=true
     ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
 esac
 
-# For Cygwin, ensure paths are in UNIX format before anything is touched.
-if $cygwin ; then
-    [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
-fi
-
-# Attempt to set APP_HOME
-# Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
-done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >&-
-APP_HOME="`pwd -P`"
-cd "$SAVED" >&-
-
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
@@ -90,7 +89,7 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
     MAX_FD_LIMIT=`ulimit -H -n`
     if [ $? -eq 0 ] ; then
         if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
@@ -114,6 +113,7 @@ fi
 if $cygwin ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
 
     # We build the pattern for arguments to be converted via cygpath
     ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
@@ -154,11 +154,19 @@ if $cygwin ; then
     esac
 fi
 
-# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
-function splitJvmOpts() {
-    JVM_OPTS=("$@")
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
 }
-eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
-JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
 
-exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index aec9973..e95643d 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -8,14 +8,14 @@
 @rem Set local scope for the variables with windows NT shell
 if "%OS%"=="Windows_NT" setlocal
 
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
-
 set DIRNAME=%~dp0
 if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
@@ -46,10 +46,9 @@ echo location of your Java installation.
 goto fail
 
 :init
-@rem Get command-line arguments, handling Windowz variants
+@rem Get command-line arguments, handling Windows variants
 
 if not "%OS%" == "Windows_NT" goto win9xME_args
-if "%@eval[2+2]" == "4" goto 4NT_args
 
 :win9xME_args
 @rem Slurp the command line arguments.
@@ -60,11 +59,6 @@ set _SKIP=2
 if "x%~1" == "x" goto execute
 
 set CMD_LINE_ARGS=%*
-goto execute
-
-:4NT_args
-@rem Get arguments from the 4NT Shell from JP Software
-set CMD_LINE_ARGS=%$
 
 :execute
 @rem Setup the command line