diff --git a/.classpath b/.classpath
index 394584d32..51cddb645 100644
--- a/.classpath
+++ b/.classpath
@@ -6,11 +6,18 @@
 	<classpathentry kind="src" path="src/test/bugtraq" output="bin/test-classes" />
 	<classpathentry kind="src" path="src/main/resources" />
 	<classpathentry kind="src" path="src/test/resources" output="bin/test-classes" />
-	<classpathentry kind="lib" path="ext/guice-4.0.jar" sourcepath="ext/src/guice-4.0.jar" />
+	<classpathentry kind="lib" path="ext/guice-5.1.0.jar" sourcepath="ext/src/guice-5.1.0.jar" />
 	<classpathentry kind="lib" path="ext/javax.inject-1.jar" sourcepath="ext/src/javax.inject-1.jar" />
 	<classpathentry kind="lib" path="ext/aopalliance-1.0.jar" sourcepath="ext/src/aopalliance-1.0.jar" />
-	<classpathentry kind="lib" path="ext/guava-18.0.jar" sourcepath="ext/src/guava-18.0.jar" />
-	<classpathentry kind="lib" path="ext/guice-servlet-4.0-gb2.jar" sourcepath="ext/src/guice-servlet-4.0-gb2.jar" />
+	<classpathentry kind="lib" path="ext/guava-27.0.1-jre.jar" sourcepath="ext/src/guava-27.0.1-jre.jar" />
+	<classpathentry kind="lib" path="ext/failureaccess-1.0.1.jar" sourcepath="ext/src/failureaccess-1.0.1.jar" />
+	<classpathentry kind="lib" path="ext/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar" />
+	<classpathentry kind="lib" path="ext/jsr305-3.0.2.jar" sourcepath="ext/src/jsr305-3.0.2.jar" />
+	<classpathentry kind="lib" path="ext/checker-qual-2.5.2.jar" sourcepath="ext/src/checker-qual-2.5.2.jar" />
+	<classpathentry kind="lib" path="ext/error_prone_annotations-2.2.0.jar" sourcepath="ext/src/error_prone_annotations-2.2.0.jar" />
+	<classpathentry kind="lib" path="ext/j2objc-annotations-1.1.jar" sourcepath="ext/src/j2objc-annotations-1.1.jar" />
+	<classpathentry kind="lib" path="ext/guice-servlet-5.1.0-gb2.jar" sourcepath="ext/src/guice-servlet-5.1.0-gb2.jar" />
+	<classpathentry kind="lib" path="ext/animal-sniffer-annotations-1.17.jar" sourcepath="ext/src/animal-sniffer-annotations-1.17.jar" />
 	<classpathentry kind="lib" path="ext/annotations-12.0.jar" sourcepath="ext/src/annotations-12.0.jar" />
 	<classpathentry kind="lib" path="ext/log4j-1.2.17.jar" sourcepath="ext/src/log4j-1.2.17.jar" />
 	<classpathentry kind="lib" path="ext/slf4j-api-1.7.29.jar" sourcepath="ext/src/slf4j-api-1.7.29.jar" />
diff --git a/build.moxie b/build.moxie
index d78733bf3..9b32963e8 100644
--- a/build.moxie
+++ b/build.moxie
@@ -116,9 +116,9 @@ properties: {
   wikitext.version : 1.4
   sshd.version: 1.7.0
   mina.version: 2.0.21
-  guice.version : 4.0
+  guice.version : 5.1.0
   # Gitblit maintains a fork of guice-servlet
-  guice-servlet.version : 4.0-gb2
+  guice-servlet.version : 5.1.0-gb2
   }
 
 # Dependencies
@@ -135,7 +135,7 @@ properties: {
 dependencies:
 - compile 'com.google.inject:guice:${guice.version}' :war :fedclient
 - compile 'com.google.inject.extensions:guice-servlet:${guice-servlet.version}' :war
-- compile 'com.google.guava:guava:18.0' :war :fedclient
+- compile 'com.google.guava:guava:27.0.1-jre' :war :fedclient
 - compile 'com.intellij:annotations:12.0' :war
 - compile 'log4j:log4j:1.2.17' :war :fedclient :manager
 - compile 'org.slf4j:slf4j-api:${slf4j.version}' :war :fedclient :manager
diff --git a/gitblit.iml b/gitblit.iml
index e2ed5b0fe..e78bdebf4 100644
--- a/gitblit.iml
+++ b/gitblit.iml
@@ -15,13 +15,13 @@
     </content>
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="module-library">
-      <library name="guice-4.0.jar">
+      <library name="guice-5.1.0.jar">
         <CLASSES>
-          <root url="jar://$MODULE_DIR$/ext/guice-4.0.jar!/" />
+          <root url="jar://$MODULE_DIR$/ext/guice-5.1.0.jar!/" />
         </CLASSES>
         <JAVADOC />
         <SOURCES>
-          <root url="jar://$MODULE_DIR$/ext/src/guice-4.0.jar!/" />
+          <root url="jar://$MODULE_DIR$/ext/src/guice-5.1.0.jar!/" />
         </SOURCES>
       </library>
     </orderEntry>
@@ -48,24 +48,99 @@
       </library>
     </orderEntry>
     <orderEntry type="module-library">
-      <library name="guava-18.0.jar">
+      <library name="guava-27.0.1-jre.jar">
         <CLASSES>
-          <root url="jar://$MODULE_DIR$/ext/guava-18.0.jar!/" />
+          <root url="jar://$MODULE_DIR$/ext/guava-27.0.1-jre.jar!/" />
         </CLASSES>
         <JAVADOC />
         <SOURCES>
-          <root url="jar://$MODULE_DIR$/ext/src/guava-18.0.jar!/" />
+          <root url="jar://$MODULE_DIR$/ext/src/guava-27.0.1-jre.jar!/" />
         </SOURCES>
       </library>
     </orderEntry>
     <orderEntry type="module-library">
-      <library name="guice-servlet-4.0-gb2.jar">
+      <library name="failureaccess-1.0.1.jar">
         <CLASSES>
-          <root url="jar://$MODULE_DIR$/ext/guice-servlet-4.0-gb2.jar!/" />
+          <root url="jar://$MODULE_DIR$/ext/failureaccess-1.0.1.jar!/" />
         </CLASSES>
         <JAVADOC />
         <SOURCES>
-          <root url="jar://$MODULE_DIR$/ext/src/guice-servlet-4.0-gb2.jar!/" />
+          <root url="jar://$MODULE_DIR$/ext/src/failureaccess-1.0.1.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="jsr305-3.0.2.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/jsr305-3.0.2.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/ext/src/jsr305-3.0.2.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="checker-qual-2.5.2.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/checker-qual-2.5.2.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/ext/src/checker-qual-2.5.2.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="error_prone_annotations-2.2.0.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/error_prone_annotations-2.2.0.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/ext/src/error_prone_annotations-2.2.0.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="j2objc-annotations-1.1.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/j2objc-annotations-1.1.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/ext/src/j2objc-annotations-1.1.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="guice-servlet-5.1.0-gb2.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/guice-servlet-5.1.0-gb2.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/ext/src/guice-servlet-5.1.0-gb2.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library">
+      <library name="animal-sniffer-annotations-1.17.jar">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/ext/animal-sniffer-annotations-1.17.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/ext/src/animal-sniffer-annotations-1.17.jar!/" />
         </SOURCES>
       </library>
     </orderEntry>
diff --git a/releases.moxie b/releases.moxie
index c7a75a926..41ad66428 100644
--- a/releases.moxie
+++ b/releases.moxie
@@ -17,6 +17,8 @@ r34: {
     additions: ~
     dependencyChanges:
       - update to JavaMail 1.5.6 (pr-1217 by @paladox)
+      - update Google Guice to 5.1.0
+      - update Google Guava to 27.0.1-jre
     contributors:
       - paladox
 }