diff --git a/build.gradle b/build.gradle
index 8ae659ccec..7940e1ab66 100644
--- a/build.gradle
+++ b/build.gradle
@@ -4,6 +4,7 @@ version '1.0-SNAPSHOT'
 apply plugin: 'java'
 apply plugin: 'kotlin'
 apply plugin: 'application'
+apply plugin: 'project-report'
 
 allprojects {
     sourceCompatibility = 1.8
@@ -42,13 +43,8 @@ configurations {
     quasar
 }
 
-// This block makes Gradle print an error and refuse to continue if we get multiple versions of the same library
-// included simultaneously.
-configurations.all() {
-    resolutionStrategy {
-        failOnVersionConflict()
-    }
-}
+// To find potential version conflicts, run "gradle htmlDependencyReport" and then look in
+// build/reports/project/dependencies/index.html for green highlighted parts of the tree.
 
 dependencies {
     compile project(':contracts')
@@ -56,26 +52,20 @@ dependencies {
     compile "com.google.code.findbugs:jsr305:3.0.1"
     compile "org.slf4j:slf4j-jdk14:1.7.13"
 
-    compile("org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version") {
-        force = true
-    }
+    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
     compile "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
 
-    compile("com.google.guava:guava:19.0") {
-        force = true     // Conflict between Quasar and Artemis
-    }
+    compile "com.google.guava:guava:19.0"
 
     // JOpt: for command line flags.
     compile "net.sf.jopt-simple:jopt-simple:4.9"
 
     // Quasar: for the bytecode rewriting for state machines.
-    quasar("co.paralleluniverse:quasar-core:${quasar_version}:jdk8@jar")
+    quasar "co.paralleluniverse:quasar-core:${quasar_version}:jdk8@jar"
 
     // Artemis: for reliable p2p message queues.
-    compile("org.apache.activemq:artemis-server:${artemis_version}") {
-        exclude group: "com.google.guava", module: "guava"   // Artemis is on Guava 18
-    }
+    compile "org.apache.activemq:artemis-server:${artemis_version}"
     compile "org.apache.activemq:artemis-core-client:${artemis_version}"
 
     // JAnsi: for drawing things to the terminal in nicely coloured ways.
@@ -89,9 +79,7 @@ dependencies {
     }
 
     // Force commons logging to version 1.2 to override Artemis, which pulls in 1.1.3 (ARTEMIS-424)
-    compile("commons-logging:commons-logging:1.2") {
-        force = true
-    }
+    compile "commons-logging:commons-logging:1.2"
 
     // Web stuff: for HTTP[S] servlets
     compile "org.eclipse.jetty:jetty-servlet:${jetty_version}"
@@ -116,6 +104,9 @@ dependencies {
     }
     compile "com.fasterxml.jackson.core:jackson-annotations:2.5.5"
 
+    // Coda Hale's Metrics: for monitoring of key statistics
+    compile "io.dropwizard.metrics:metrics-core:3.1.2"
+
     // Unit testing helpers.
     testCompile 'junit:junit:4.12'
     testCompile 'com.google.jimfs:jimfs:1.1'   // in memory java.nio filesystem.
diff --git a/core/build.gradle b/core/build.gradle
index 0d8b218901..caf2a4d3b8 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -35,7 +35,7 @@ dependencies {
     compile "com.google.guava:guava:19.0"
 
     // RxJava: observable streams of events.
-    compile "io.reactivex:rxkotlin:0.40.1"
+    compile "io.reactivex:rxjava:1.0.17"
 
     // Kryo: object graph serialization.
     compile "com.esotericsoftware:kryo:3.0.3"
diff --git a/core/src/main/kotlin/core/utilities/ProgressTracker.kt b/core/src/main/kotlin/core/utilities/ProgressTracker.kt
index 1bf99c29f2..db8dea4e9e 100644
--- a/core/src/main/kotlin/core/utilities/ProgressTracker.kt
+++ b/core/src/main/kotlin/core/utilities/ProgressTracker.kt
@@ -11,7 +11,7 @@ package core.utilities
 import core.TransientProperty
 import rx.Observable
 import rx.Subscription
-import rx.lang.kotlin.BehaviourSubject
+import rx.subjects.BehaviorSubject
 import rx.subjects.PublishSubject
 import java.util.*
 
@@ -54,7 +54,7 @@ class ProgressTracker(vararg steps: Step) {
 
     /** This class makes it easier to relabel a step on the fly, to provide transient information. */
     open class RelabelableStep(currentLabel: String) : Step(currentLabel) {
-        override val changes = BehaviourSubject<Change>()
+        override val changes = BehaviorSubject.create<Change>()
 
         var currentLabel: String = currentLabel
             set(value) {