diff --git a/app/build.gradle b/app/build.gradle
index 2b189c60b..845e3dd7f 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 apply plugin: 'checkstyle'
 apply plugin: 'pmd'
 
-/* gets the version name from the latest Git tag, stripping the leading v off */
+/* gets the version name from the latest Git tag */
 def getVersionName = { ->
     def stdout = new ByteArrayOutputStream()
     exec {
@@ -192,7 +192,7 @@ task checkstyle(type: Checkstyle) {
 }
 
 pmd {
-    toolVersion = '5.5.1'
+    toolVersion = '6.20.0'
     consoleOutput = true
 }
 
@@ -202,7 +202,6 @@ task pmdMain(type: Pmd) {
     ruleSets = [] // otherwise defaults clash with the list in rules.xml
     source 'src/main/java'
     include '**/*.java'
-    exclude '**/kellinwood/**/*.java'
 }
 
 task pmdTest(type: Pmd) {
diff --git a/config/pmd/rules-main.xml b/config/pmd/rules-main.xml
index 5b33b45d8..81d6ca133 100644
--- a/config/pmd/rules-main.xml
+++ b/config/pmd/rules-main.xml
@@ -1,9 +1,13 @@
 <?xml version="1.0"?>
 <ruleset name="Custom ruleset (for main code)"
-        xmlns="http://pmd.sf.net/ruleset/1.0.0"
-        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
-        xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+         xmlns="http://pmd.sf.net/ruleset/1.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
+         xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+  <description>
+    Rules for the project code aka "main".
+  </description>
+
+  <!-- TODO <rule ref="category/java/errorprone.xml/CloseResource"/> -->
 
-    <rule ref="rulesets/java/imports.xml" />
 </ruleset>
diff --git a/config/pmd/rules-test.xml b/config/pmd/rules-test.xml
index 0889f5bcf..1d9d81a86 100644
--- a/config/pmd/rules-test.xml
+++ b/config/pmd/rules-test.xml
@@ -1,11 +1,17 @@
 <?xml version="1.0"?>
 <ruleset name="Custom ruleset (for tests)"
-        xmlns="http://pmd.sf.net/ruleset/1.0.0"
-        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
-        xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+         xmlns="http://pmd.sf.net/ruleset/1.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
+         xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+  <description>
+    Rules for the test harness code aka "androidTest" and "test".
+  </description>
+
+  <!-- ideally these would be promoted to rules.xml -->
+  <rule ref="category/java/bestpractices.xml/ConstantsInInterface"/>
+  <rule ref="category/java/bestpractices.xml/UseCollectionIsEmpty"/>
+  <rule ref="category/java/errorprone.xml/AvoidFieldNameMatchingMethodName"/>
+  <rule ref="category/java/errorprone.xml/AvoidFieldNameMatchingTypeName"/>
 
-    <rule ref="rulesets/java/imports.xml">
-        <exclude name="TooManyStaticImports" /><!-- Static imports are commonly used for JUnit tests -->
-    </rule>
 </ruleset>
diff --git a/config/pmd/rules.xml b/config/pmd/rules.xml
index e9a161577..64b55aa49 100644
--- a/config/pmd/rules.xml
+++ b/config/pmd/rules.xml
@@ -1,52 +1,52 @@
 <?xml version="1.0"?>
 <ruleset name="Custom ruleset"
-        xmlns="http://pmd.sf.net/ruleset/1.0.0"
-        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
-        xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+         xmlns="http://pmd.sf.net/ruleset/1.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
+         xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">
+  <description>
+    Rules for the whole project
+  </description>
 
-    <rule ref="rulesets/java/basic.xml">
-        <exclude name="CollapsibleIfStatements"/> <!--sometimes forces hard to read code-->
-    </rule>
-    <rule ref="rulesets/java/unusedcode.xml"/>
-    <rule ref="rulesets/java/android.xml"/>
-    <rule ref="rulesets/java/clone.xml"/>
-    <rule ref="rulesets/java/finalizers.xml"/>
-    <rule ref="rulesets/java/migrating.xml"/>
-    <rule ref="rulesets/java/unnecessary.xml">
-        <exclude name="UselessParentheses"/> <!--Too nitpicky-->
-    </rule>
-    <rule ref="rulesets/java/empty.xml">
-        <exclude name="EmptyCatchBlock"/> <!--Ignoring an exception-->
-        <exclude name="EmptyWhileStmt"/> <!--Can be useful sometimes-->
-    </rule>
-    <rule ref="rulesets/java/optimizations.xml/PrematureDeclaration"/>
-    <rule ref="rulesets/java/optimizations.xml/AddEmptyString"/>
-    <rule ref="rulesets/java/optimizations.xml/UseArraysAsList"/>
-    <rule ref="rulesets/java/optimizations.xml/UnnecessaryWrapperObjectCreation"/>
-
-    <rule ref="rulesets/java/controversial.xml/UnnecessaryConstructor"/>
-    <rule ref="rulesets/java/controversial.xml/UnnecessaryParentheses"/>
-
-    <rule ref="rulesets/java/strictexception.xml/AvoidRethrowingException"/>
-    <rule ref="rulesets/java/strictexception.xml/AvoidCatchingThrowable"/>
-    <rule ref="rulesets/java/strictexception.xml/AvoidCatchingNPE"/>
-    <rule ref="rulesets/java/strictexception.xml/DoNotExtendJavaLangError"/>
-    <rule ref="rulesets/java/strictexception.xml/DoNotThrowExceptionInFinally"/>
-    <rule ref="rulesets/java/strictexception.xml/AvoidThrowingNewInstanceOfSameException"/>
-    <rule ref="rulesets/java/strictexception.xml/AvoidThrowingNullPointerException"/>
-
-    <rule ref="rulesets/java/design.xml/FinalFieldCouldBeStatic"/>
-    <rule ref="rulesets/java/design.xml/CloseResource"/>
-    <rule ref="rulesets/java/design.xml/DefaultLabelNotLastInSwitchStmt"/>
-    <rule ref="rulesets/java/design.xml/UnnecessaryLocalBeforeReturn"/>
-    <rule ref="rulesets/java/design.xml/NonCaseLabelInSwitchStatement"/>
-    <rule ref="rulesets/java/design.xml/EqualsNull"/>
-    <rule ref="rulesets/java/design.xml/IdempotentOperations"/>
-    <rule ref="rulesets/java/design.xml/ImmutableField"/>
-    <rule ref="rulesets/java/design.xml/SingularField"/>
-    <rule ref="rulesets/java/design.xml/SimplifyBooleanReturns"/>
-    <rule ref="rulesets/java/design.xml/SimplifyBooleanExpressions"/>
-    <rule ref="rulesets/java/design.xml/LogicInversion"/>
+  <rule ref="category/java/bestpractices.xml/AbstractClassWithoutAbstractMethod"/>
+  <rule ref="category/java/bestpractices.xml/AvoidReassigningLoopVariables"/>
+  <rule ref="category/java/bestpractices.xml/DefaultLabelNotLastInSwitchStmt"/>
+  <rule ref="category/java/bestpractices.xml/MissingOverride"/>
+  <rule ref="category/java/bestpractices.xml/UnusedFormalParameter"/>
+  <rule ref="category/java/bestpractices.xml/UnusedLocalVariable"/>
+  <rule ref="category/java/bestpractices.xml/UnusedPrivateField"/>
+  <rule ref="category/java/bestpractices.xml/UnusedPrivateMethod"/>
+  <rule ref="category/java/codestyle.xml/UnnecessaryConstructor"/>
+  <rule ref="category/java/codestyle.xml/UnnecessaryLocalBeforeReturn"/>
+  <rule ref="category/java/design.xml/AvoidRethrowingException"/>
+  <rule ref="category/java/design.xml/AvoidThrowingNewInstanceOfSameException"/>
+  <rule ref="category/java/design.xml/AvoidThrowingNullPointerException"/>
+  <rule ref="category/java/design.xml/DoNotExtendJavaLangError"/>
+  <rule ref="category/java/design.xml/FinalFieldCouldBeStatic"/>
+  <rule ref="category/java/design.xml/ImmutableField"/>
+  <rule ref="category/java/design.xml/LogicInversion"/>
+  <rule ref="category/java/design.xml/SimplifyBooleanExpressions"/>
+  <rule ref="category/java/design.xml/SimplifyBooleanReturns"/>
+  <rule ref="category/java/design.xml/SingularField"/>
+  <rule ref="category/java/errorprone.xml/AssignmentInOperand"/>
+  <rule ref="category/java/errorprone.xml/AvoidAssertAsIdentifier"/>
+  <rule ref="category/java/errorprone.xml/AvoidBranchingStatementAsLastInLoop"/>
+  <rule ref="category/java/errorprone.xml/AvoidCallingFinalize"/>
+  <rule ref="category/java/errorprone.xml/AvoidCatchingNPE"/>
+  <rule ref="category/java/errorprone.xml/AvoidCatchingThrowable"/>
+  <rule ref="category/java/errorprone.xml/AvoidMultipleUnaryOperators"/>
+  <rule ref="category/java/errorprone.xml/AvoidUsingOctalValues"/>
+  <rule ref="category/java/errorprone.xml/BrokenNullCheck"/>
+  <rule ref="category/java/errorprone.xml/CallSuperFirst"/>
+  <rule ref="category/java/errorprone.xml/CallSuperLast"/>
+  <rule ref="category/java/errorprone.xml/DoNotHardCodeSDCard" />
+  <rule ref="category/java/errorprone.xml/DoNotThrowExceptionInFinally"/>
+  <rule ref="category/java/errorprone.xml/EqualsNull"/>
+  <rule ref="category/java/errorprone.xml/IdempotentOperations"/>
+  <rule ref="category/java/errorprone.xml/NonCaseLabelInSwitchStatement"/>
+  <rule ref="category/java/performance.xml/AddEmptyString"/>
+  <rule ref="category/java/performance.xml/UnnecessaryWrapperObjectCreation"/>
+  <rule ref="category/java/performance.xml/UseArraysAsList"/>
+  <rule ref="category/java/security.xml"/>
 
 </ruleset>